diff --git a/pandas/_config/config.py b/pandas/_config/config.py
index 47913c2a1cf7d..455f800073c15 100644
--- a/pandas/_config/config.py
+++ b/pandas/_config/config.py
@@ -48,6 +48,8 @@
 
 """
 
+from __future__ import annotations
+
 from collections import namedtuple
 from contextlib import (
     ContextDecorator,
@@ -57,12 +59,7 @@
 from typing import (
     Any,
     Callable,
-    Dict,
     Iterable,
-    List,
-    Optional,
-    Tuple,
-    Type,
     cast,
 )
 import warnings
@@ -73,16 +70,16 @@
 RegisteredOption = namedtuple("RegisteredOption", "key defval doc validator cb")
 
 # holds deprecated option metadata
-_deprecated_options: Dict[str, DeprecatedOption] = {}
+_deprecated_options: dict[str, DeprecatedOption] = {}
 
 # holds registered option metadata
-_registered_options: Dict[str, RegisteredOption] = {}
+_registered_options: dict[str, RegisteredOption] = {}
 
 # holds the current values for registered options
-_global_config: Dict[str, Any] = {}
+_global_config: dict[str, Any] = {}
 
 # keys which have a special meaning
-_reserved_keys: List[str] = ["all"]
+_reserved_keys: list[str] = ["all"]
 
 
 class OptionError(AttributeError, KeyError):
@@ -194,7 +191,7 @@ def get_default_val(pat: str):
 class DictWrapper:
     """ provide attribute-style access to a nested dict"""
 
-    def __init__(self, d: Dict[str, Any], prefix: str = ""):
+    def __init__(self, d: dict[str, Any], prefix: str = ""):
         object.__setattr__(self, "d", d)
         object.__setattr__(self, "prefix", prefix)
 
@@ -428,8 +425,8 @@ def register_option(
     key: str,
     defval: object,
     doc: str = "",
-    validator: Optional[Callable[[Any], Any]] = None,
-    cb: Optional[Callable[[str], Any]] = None,
+    validator: Callable[[Any], Any] | None = None,
+    cb: Callable[[str], Any] | None = None,
 ) -> None:
     """
     Register an option in the package-wide pandas config object
@@ -500,7 +497,7 @@ def register_option(
 
 
 def deprecate_option(
-    key: str, msg: Optional[str] = None, rkey: Optional[str] = None, removal_ver=None
+    key: str, msg: str | None = None, rkey: str | None = None, removal_ver=None
 ) -> None:
     """
     Mark option `key` as deprecated, if code attempts to access this option,
@@ -547,7 +544,7 @@ def deprecate_option(
 # functions internal to the module
 
 
-def _select_options(pat: str) -> List[str]:
+def _select_options(pat: str) -> list[str]:
     """
     returns a list of keys matching `pat`
 
@@ -565,7 +562,7 @@ def _select_options(pat: str) -> List[str]:
     return [k for k in keys if re.search(pat, k, re.I)]
 
 
-def _get_root(key: str) -> Tuple[Dict[str, Any], str]:
+def _get_root(key: str) -> tuple[dict[str, Any], str]:
     path = key.split(".")
     cursor = _global_config
     for p in path[:-1]:
@@ -674,7 +671,7 @@ def pp_options_list(keys: Iterable[str], width=80, _print: bool = False):
     from itertools import groupby
     from textwrap import wrap
 
-    def pp(name: str, ks: Iterable[str]) -> List[str]:
+    def pp(name: str, ks: Iterable[str]) -> list[str]:
         pfx = "- " + name + ".[" if name else ""
         ls = wrap(
             ", ".join(ks),
@@ -687,7 +684,7 @@ def pp(name: str, ks: Iterable[str]) -> List[str]:
             ls[-1] = ls[-1] + "]"
         return ls
 
-    ls: List[str] = []
+    ls: list[str] = []
     singles = [x for x in sorted(keys) if x.find(".") < 0]
     if singles:
         ls += pp("", singles)
@@ -760,7 +757,7 @@ def inner(key: str, *args, **kwds):
 # arg in register_option
 
 
-def is_type_factory(_type: Type[Any]) -> Callable[[Any], None]:
+def is_type_factory(_type: type[Any]) -> Callable[[Any], None]:
     """
 
     Parameters
@@ -826,7 +823,7 @@ def inner(x) -> None:
     return inner
 
 
-def is_nonnegative_int(value: Optional[int]) -> None:
+def is_nonnegative_int(value: int | None) -> None:
     """
     Verify that value is None or a positive int.
 
diff --git a/pandas/_config/display.py b/pandas/_config/display.py
index ec819481525da..df2c3ad36c855 100644
--- a/pandas/_config/display.py
+++ b/pandas/_config/display.py
@@ -2,15 +2,16 @@
 Unopinionated display configuration.
 """
 
+from __future__ import annotations
+
 import locale
 import sys
-from typing import Optional
 
 from pandas._config import config as cf
 
 # -----------------------------------------------------------------------------
 # Global formatting options
-_initial_defencoding: Optional[str] = None
+_initial_defencoding: str | None = None
 
 
 def detect_console_encoding() -> str:
diff --git a/pandas/_testing/_io.py b/pandas/_testing/_io.py
index c77b9172e2091..58ce9b17909bb 100644
--- a/pandas/_testing/_io.py
+++ b/pandas/_testing/_io.py
@@ -1,11 +1,11 @@
+from __future__ import annotations
+
 import bz2
 from functools import wraps
 import gzip
 from typing import (
     Any,
     Callable,
-    Optional,
-    Tuple,
 )
 import zipfile
 
@@ -272,9 +272,7 @@ def can_connect(url, error_classes=None):
 # File-IO
 
 
-def round_trip_pickle(
-    obj: Any, path: Optional[FilePathOrBuffer] = None
-) -> FrameOrSeries:
+def round_trip_pickle(obj: Any, path: FilePathOrBuffer | None = None) -> FrameOrSeries:
     """
     Pickle an object and then read it again.
 
@@ -298,7 +296,7 @@ def round_trip_pickle(
         return pd.read_pickle(temp_path)
 
 
-def round_trip_pathlib(writer, reader, path: Optional[str] = None):
+def round_trip_pathlib(writer, reader, path: str | None = None):
     """
     Write an object to file specified by a pathlib.Path and read it back
 
@@ -327,7 +325,7 @@ def round_trip_pathlib(writer, reader, path: Optional[str] = None):
     return obj
 
 
-def round_trip_localpath(writer, reader, path: Optional[str] = None):
+def round_trip_localpath(writer, reader, path: str | None = None):
     """
     Write an object to file specified by a py.path LocalPath and read it back.
 
@@ -375,7 +373,7 @@ def write_to_compressed(compression, path, data, dest="test"):
     ------
     ValueError : An invalid compression value was passed in.
     """
-    args: Tuple[Any, ...] = (data,)
+    args: tuple[Any, ...] = (data,)
     mode = "wb"
     method = "write"
     compress_method: Callable
diff --git a/pandas/_testing/_warnings.py b/pandas/_testing/_warnings.py
index ee32abe19278e..027a53edb1810 100644
--- a/pandas/_testing/_warnings.py
+++ b/pandas/_testing/_warnings.py
@@ -1,10 +1,10 @@
+from __future__ import annotations
+
 from contextlib import contextmanager
 import re
 from typing import (
-    Optional,
     Sequence,
     Type,
-    Union,
     cast,
 )
 import warnings
@@ -12,11 +12,11 @@
 
 @contextmanager
 def assert_produces_warning(
-    expected_warning: Optional[Union[Type[Warning], bool]] = Warning,
+    expected_warning: type[Warning] | bool | None = Warning,
     filter_level="always",
     check_stacklevel: bool = True,
     raise_on_extra_warnings: bool = True,
-    match: Optional[str] = None,
+    match: str | None = None,
 ):
     """
     Context manager for running code expected to either raise a specific
@@ -99,8 +99,8 @@ class for all warnings. To check that no warning is returned,
 def _assert_caught_expected_warning(
     *,
     caught_warnings: Sequence[warnings.WarningMessage],
-    expected_warning: Type[Warning],
-    match: Optional[str],
+    expected_warning: type[Warning],
+    match: str | None,
     check_stacklevel: bool,
 ) -> None:
     """Assert that there was the expected warning among the caught warnings."""
@@ -135,7 +135,7 @@ def _assert_caught_expected_warning(
 def _assert_caught_no_extra_warnings(
     *,
     caught_warnings: Sequence[warnings.WarningMessage],
-    expected_warning: Optional[Union[Type[Warning], bool]],
+    expected_warning: type[Warning] | bool | None,
 ) -> None:
     """Assert that no extra warnings apart from the expected ones are caught."""
     extra_warnings = []
@@ -157,7 +157,7 @@ def _assert_caught_no_extra_warnings(
 
 def _is_unexpected_warning(
     actual_warning: warnings.WarningMessage,
-    expected_warning: Optional[Union[Type[Warning], bool]],
+    expected_warning: type[Warning] | bool | None,
 ) -> bool:
     """Check if the actual warning issued is unexpected."""
     if actual_warning and not expected_warning:
diff --git a/pandas/_testing/asserters.py b/pandas/_testing/asserters.py
index 4f61ceee4d66b..912039b7571bc 100644
--- a/pandas/_testing/asserters.py
+++ b/pandas/_testing/asserters.py
@@ -1,7 +1,6 @@
-from typing import (
-    Union,
-    cast,
-)
+from __future__ import annotations
+
+from typing import cast
 import warnings
 
 import numpy as np
@@ -56,8 +55,8 @@
 def assert_almost_equal(
     left,
     right,
-    check_dtype: Union[bool, str] = "equiv",
-    check_less_precise: Union[bool, int, NoDefault] = no_default,
+    check_dtype: bool | str = "equiv",
+    check_less_precise: bool | int | NoDefault = no_default,
     rtol: float = 1.0e-5,
     atol: float = 1.0e-8,
     **kwargs,
@@ -169,7 +168,7 @@ def assert_almost_equal(
         )
 
 
-def _get_tol_from_less_precise(check_less_precise: Union[bool, int]) -> float:
+def _get_tol_from_less_precise(check_less_precise: bool | int) -> float:
     """
     Return the tolerance equivalent to the deprecated `check_less_precise`
     parameter.
@@ -247,9 +246,9 @@ def assert_dict_equal(left, right, compare_keys: bool = True):
 def assert_index_equal(
     left: Index,
     right: Index,
-    exact: Union[bool, str] = "equiv",
+    exact: bool | str = "equiv",
     check_names: bool = True,
-    check_less_precise: Union[bool, int, NoDefault] = no_default,
+    check_less_precise: bool | int | NoDefault = no_default,
     check_exact: bool = True,
     check_categorical: bool = True,
     check_order: bool = True,
@@ -429,7 +428,7 @@ def _get_ilevel_values(index, level):
             assert_categorical_equal(left._values, right._values, obj=f"{obj} category")
 
 
-def assert_class_equal(left, right, exact: Union[bool, str] = True, obj="Input"):
+def assert_class_equal(left, right, exact: bool | str = True, obj="Input"):
     """
     Checks classes are equal.
     """
diff --git a/pandas/_testing/contexts.py b/pandas/_testing/contexts.py
index a14e87c04c913..e20d2d58e499f 100644
--- a/pandas/_testing/contexts.py
+++ b/pandas/_testing/contexts.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from contextlib import contextmanager
 import os
 from pathlib import Path
@@ -8,7 +10,6 @@
 from typing import (
     IO,
     Any,
-    Union,
 )
 
 import numpy as np
@@ -111,7 +112,7 @@ def ensure_clean(filename=None, return_filelike: bool = False, **kwargs: Any):
 
     path.touch()
 
-    handle_or_str: Union[str, IO] = str(path)
+    handle_or_str: str | IO = str(path)
     if return_filelike:
         kwargs.setdefault("mode", "w+b")
         handle_or_str = open(path, **kwargs)
diff --git a/pandas/compat/_optional.py b/pandas/compat/_optional.py
index a26da75d921ef..cf00618a7b2b9 100644
--- a/pandas/compat/_optional.py
+++ b/pandas/compat/_optional.py
@@ -1,8 +1,9 @@
+from __future__ import annotations
+
 import distutils.version
 import importlib
 import sys
 import types
-from typing import Optional
 import warnings
 
 # Update install.rst when updating versions!
@@ -63,7 +64,7 @@ def import_optional_dependency(
     name: str,
     extra: str = "",
     errors: str = "raise",
-    min_version: Optional[str] = None,
+    min_version: str | None = None,
 ):
     """
     Import an optional dependency.
diff --git a/pandas/core/accessor.py b/pandas/core/accessor.py
index 2b6dd379ea47c..c31368f179ef0 100644
--- a/pandas/core/accessor.py
+++ b/pandas/core/accessor.py
@@ -4,33 +4,30 @@
 that can be mixed into or pinned onto other pandas classes.
 
 """
-from typing import (
-    FrozenSet,
-    List,
-    Set,
-)
+from __future__ import annotations
+
 import warnings
 
 from pandas.util._decorators import doc
 
 
 class DirNamesMixin:
-    _accessors: Set[str] = set()
-    _hidden_attrs: FrozenSet[str] = frozenset()
+    _accessors: set[str] = set()
+    _hidden_attrs: frozenset[str] = frozenset()
 
-    def _dir_deletions(self) -> Set[str]:
+    def _dir_deletions(self) -> set[str]:
         """
         Delete unwanted __dir__ for this object.
         """
         return self._accessors | self._hidden_attrs
 
-    def _dir_additions(self) -> Set[str]:
+    def _dir_additions(self) -> set[str]:
         """
         Add additional __dir__ for this object.
         """
         return {accessor for accessor in self._accessors if hasattr(self, accessor)}
 
-    def __dir__(self) -> List[str]:
+    def __dir__(self) -> list[str]:
         """
         Provide method name lookup and completion.
 
diff --git a/pandas/core/base.py b/pandas/core/base.py
index 05ec9d543976a..42f52618eb07b 100644
--- a/pandas/core/base.py
+++ b/pandas/core/base.py
@@ -2,15 +2,13 @@
 Base and utility classes for pandas objects.
 """
 
+from __future__ import annotations
+
 import textwrap
 from typing import (
     TYPE_CHECKING,
     Any,
-    Dict,
-    FrozenSet,
-    Optional,
     TypeVar,
-    Union,
     cast,
 )
 
@@ -64,7 +62,7 @@
 if TYPE_CHECKING:
     from pandas import Categorical
 
-_shared_docs: Dict[str, str] = {}
+_shared_docs: dict[str, str] = {}
 _indexops_doc_kwargs = {
     "klass": "IndexOpsMixin",
     "inplace": "",
@@ -81,7 +79,7 @@ class PandasObject(DirNamesMixin):
     """
 
     # results from calls to methods decorated with cache_readonly get added to _cache
-    _cache: Dict[str, Any]
+    _cache: dict[str, Any]
 
     @property
     def _constructor(self):
@@ -97,7 +95,7 @@ def __repr__(self) -> str:
         # Should be overwritten by base classes
         return object.__repr__(self)
 
-    def _reset_cache(self, key: Optional[str] = None) -> None:
+    def _reset_cache(self, key: str | None = None) -> None:
         """
         Reset cached properties. If ``key`` is passed, only clears that key.
         """
@@ -170,7 +168,7 @@ class SelectionMixin:
     object sub-classes need to define: obj, exclusions
     """
 
-    _selection: Optional[IndexLabel] = None
+    _selection: IndexLabel | None = None
     _internal_names = ["_cache", "__setstate__"]
     _internal_names_set = set(_internal_names)
 
@@ -286,7 +284,7 @@ class IndexOpsMixin(OpsMixin):
 
     # ndarray compatibility
     __array_priority__ = 1000
-    _hidden_attrs: FrozenSet[str] = frozenset(
+    _hidden_attrs: frozenset[str] = frozenset(
         ["tolist"]  # tolist is not deprecated, just suppressed in the __dir__
     )
 
@@ -296,7 +294,7 @@ def dtype(self) -> DtypeObj:
         raise AbstractMethodError(self)
 
     @property
-    def _values(self) -> Union[ExtensionArray, np.ndarray]:
+    def _values(self) -> ExtensionArray | np.ndarray:
         # must be defined here as a property for mypy
         raise AbstractMethodError(self)
 
@@ -437,7 +435,7 @@ def array(self) -> ExtensionArray:
 
     def to_numpy(
         self,
-        dtype: Optional[Dtype] = None,
+        dtype: Dtype | None = None,
         copy: bool = False,
         na_value=lib.no_default,
         **kwargs,
@@ -1139,7 +1137,7 @@ def _memory_usage(self, deep: bool = False) -> int:
             """
         ),
     )
-    def factorize(self, sort: bool = False, na_sentinel: Optional[int] = -1):
+    def factorize(self, sort: bool = False, na_sentinel: int | None = -1):
         return algorithms.factorize(self, sort=sort, na_sentinel=na_sentinel)
 
     _shared_docs[
@@ -1257,5 +1255,5 @@ def drop_duplicates(self, keep="first"):
         return self[~duplicated]  # type: ignore[index]
 
     @final
-    def _duplicated(self, keep: Union[str, bool] = "first") -> np.ndarray:
+    def _duplicated(self, keep: str | bool = "first") -> np.ndarray:
         return duplicated(self._values, keep=keep)
diff --git a/pandas/core/shared_docs.py b/pandas/core/shared_docs.py
index 66d84ef85880c..a4ee4bb636450 100644
--- a/pandas/core/shared_docs.py
+++ b/pandas/core/shared_docs.py
@@ -1,6 +1,6 @@
-from typing import Dict
+from __future__ import annotations
 
-_shared_docs: Dict[str, str] = {}
+_shared_docs: dict[str, str] = {}
 
 _shared_docs[
     "aggregate"
diff --git a/pandas/io/html.py b/pandas/io/html.py
index 7541e5d62fd1e..43584e2cecfc4 100644
--- a/pandas/io/html.py
+++ b/pandas/io/html.py
@@ -4,18 +4,15 @@
 
 """
 
+from __future__ import annotations
+
 from collections import abc
 import numbers
 import os
 import re
 from typing import (
-    Dict,
-    List,
-    Optional,
     Pattern,
     Sequence,
-    Tuple,
-    Union,
 )
 
 from pandas._typing import FilePathOrBuffer
@@ -447,7 +444,7 @@ def _expand_colspan_rowspan(self, rows):
         to subsequent cells.
         """
         all_texts = []  # list of rows, each a list of str
-        remainder: List[Tuple[int, str, int]] = []  # list of (index, text, nrows)
+        remainder: list[tuple[int, str, int]] = []  # list of (index, text, nrows)
 
         for tr in rows:
             texts = []  # the output for this row
@@ -940,21 +937,21 @@ def _parse(flavor, io, match, attrs, encoding, displayed_only, **kwargs):
 @deprecate_nonkeyword_arguments(version="2.0")
 def read_html(
     io: FilePathOrBuffer,
-    match: Union[str, Pattern] = ".+",
-    flavor: Optional[str] = None,
-    header: Optional[Union[int, Sequence[int]]] = None,
-    index_col: Optional[Union[int, Sequence[int]]] = None,
-    skiprows: Optional[Union[int, Sequence[int], slice]] = None,
-    attrs: Optional[Dict[str, str]] = None,
+    match: str | Pattern = ".+",
+    flavor: str | None = None,
+    header: int | Sequence[int] | None = None,
+    index_col: int | Sequence[int] | None = None,
+    skiprows: int | Sequence[int] | slice | None = None,
+    attrs: dict[str, str] | None = None,
     parse_dates: bool = False,
-    thousands: Optional[str] = ",",
-    encoding: Optional[str] = None,
+    thousands: str | None = ",",
+    encoding: str | None = None,
     decimal: str = ".",
-    converters: Optional[Dict] = None,
+    converters: dict | None = None,
     na_values=None,
     keep_default_na: bool = True,
     displayed_only: bool = True,
-) -> List[DataFrame]:
+) -> list[DataFrame]:
     r"""
     Read HTML tables into a ``list`` of ``DataFrame`` objects.
 
diff --git a/pandas/io/spss.py b/pandas/io/spss.py
index fb0ecee995463..533cf7a7a6331 100644
--- a/pandas/io/spss.py
+++ b/pandas/io/spss.py
@@ -1,9 +1,7 @@
+from __future__ import annotations
+
 from pathlib import Path
-from typing import (
-    Optional,
-    Sequence,
-    Union,
-)
+from typing import Sequence
 
 from pandas.compat._optional import import_optional_dependency
 
@@ -15,8 +13,8 @@
 
 
 def read_spss(
-    path: Union[str, Path],
-    usecols: Optional[Sequence[str]] = None,
+    path: str | Path,
+    usecols: Sequence[str] | None = None,
     convert_categoricals: bool = True,
 ) -> DataFrame:
     """
diff --git a/pandas/io/sql.py b/pandas/io/sql.py
index 4a83814c52ade..d797fa51984d6 100644
--- a/pandas/io/sql.py
+++ b/pandas/io/sql.py
@@ -3,6 +3,8 @@
 retrieval and to reduce dependency on DB-specific API.
 """
 
+from __future__ import annotations
+
 from contextlib import contextmanager
 from datetime import (
     date,
@@ -14,12 +16,8 @@
 import re
 from typing import (
     Any,
-    Dict,
     Iterator,
-    List,
-    Optional,
     Sequence,
-    Union,
     cast,
     overload,
 )
@@ -57,7 +55,7 @@ class DatabaseError(IOError):
 # -----------------------------------------------------------------------------
 # -- Helper functions
 
-_SQLALCHEMY_INSTALLED: Optional[bool] = None
+_SQLALCHEMY_INSTALLED: bool | None = None
 
 
 def _is_sqlalchemy_connectable(con):
@@ -111,7 +109,7 @@ def _process_parse_dates_argument(parse_dates):
 
 
 def _handle_date_column(
-    col, utc: Optional[bool] = None, format: Optional[Union[str, Dict[str, Any]]] = None
+    col, utc: bool | None = None, format: str | dict[str, Any] | None = None
 ):
     if isinstance(format, dict):
         # GH35185 Allow custom error values in parse_dates argument of
@@ -165,7 +163,7 @@ def _wrap_result(
     index_col=None,
     coerce_float: bool = True,
     parse_dates=None,
-    dtype: Optional[DtypeArg] = None,
+    dtype: DtypeArg | None = None,
 ):
     """Wrap result set of query in a DataFrame."""
     frame = DataFrame.from_records(data, columns=columns, coerce_float=coerce_float)
@@ -244,13 +242,13 @@ def read_sql_table(
 def read_sql_table(
     table_name: str,
     con,
-    schema: Optional[str] = None,
-    index_col: Optional[Union[str, Sequence[str]]] = None,
+    schema: str | None = None,
+    index_col: str | Sequence[str] | None = None,
     coerce_float: bool = True,
     parse_dates=None,
     columns=None,
-    chunksize: Optional[int] = None,
-) -> Union[DataFrame, Iterator[DataFrame]]:
+    chunksize: int | None = None,
+) -> DataFrame | Iterator[DataFrame]:
     """
     Read SQL database table into a DataFrame.
 
@@ -345,7 +343,7 @@ def read_sql_query(
     params=None,
     parse_dates=None,
     chunksize: None = None,
-    dtype: Optional[DtypeArg] = None,
+    dtype: DtypeArg | None = None,
 ) -> DataFrame:
     ...
 
@@ -359,7 +357,7 @@ def read_sql_query(
     params=None,
     parse_dates=None,
     chunksize: int = 1,
-    dtype: Optional[DtypeArg] = None,
+    dtype: DtypeArg | None = None,
 ) -> Iterator[DataFrame]:
     ...
 
@@ -371,9 +369,9 @@ def read_sql_query(
     coerce_float: bool = True,
     params=None,
     parse_dates=None,
-    chunksize: Optional[int] = None,
-    dtype: Optional[DtypeArg] = None,
-) -> Union[DataFrame, Iterator[DataFrame]]:
+    chunksize: int | None = None,
+    dtype: DtypeArg | None = None,
+) -> DataFrame | Iterator[DataFrame]:
     """
     Read SQL query into a DataFrame.
 
@@ -474,13 +472,13 @@ def read_sql(
 def read_sql(
     sql,
     con,
-    index_col: Optional[Union[str, Sequence[str]]] = None,
+    index_col: str | Sequence[str] | None = None,
     coerce_float: bool = True,
     params=None,
     parse_dates=None,
     columns=None,
-    chunksize: Optional[int] = None,
-) -> Union[DataFrame, Iterator[DataFrame]]:
+    chunksize: int | None = None,
+) -> DataFrame | Iterator[DataFrame]:
     """
     Read SQL query or database table into a DataFrame.
 
@@ -638,13 +636,13 @@ def to_sql(
     frame,
     name: str,
     con,
-    schema: Optional[str] = None,
+    schema: str | None = None,
     if_exists: str = "fail",
     index: bool = True,
     index_label=None,
-    chunksize: Optional[int] = None,
-    dtype: Optional[DtypeArg] = None,
-    method: Optional[str] = None,
+    chunksize: int | None = None,
+    dtype: DtypeArg | None = None,
+    method: str | None = None,
 ) -> None:
     """
     Write records stored in a DataFrame to a SQL database.
@@ -717,7 +715,7 @@ def to_sql(
     )
 
 
-def has_table(table_name: str, con, schema: Optional[str] = None):
+def has_table(table_name: str, con, schema: str | None = None):
     """
     Check if DataBase has named table.
 
@@ -763,7 +761,7 @@ def _engine_builder(con):
 
 
 def pandasSQL_builder(
-    con, schema: Optional[str] = None, meta=None, is_cursor: bool = False
+    con, schema: str | None = None, meta=None, is_cursor: bool = False
 ):
     """
     Convenience function to return the correct PandasSQL subclass based on the
@@ -802,7 +800,7 @@ def __init__(
         index_label=None,
         schema=None,
         keys=None,
-        dtype: Optional[DtypeArg] = None,
+        dtype: DtypeArg | None = None,
     ):
         self.name = name
         self.pd_sql = pandas_sql_engine
@@ -854,7 +852,7 @@ def create(self):
         else:
             self._execute_create()
 
-    def _execute_insert(self, conn, keys: List[str], data_iter):
+    def _execute_insert(self, conn, keys: list[str], data_iter):
         """
         Execute SQL statement inserting data
 
@@ -869,7 +867,7 @@ def _execute_insert(self, conn, keys: List[str], data_iter):
         data = [dict(zip(keys, row)) for row in data_iter]
         conn.execute(self.table.insert(), data)
 
-    def _execute_insert_multi(self, conn, keys: List[str], data_iter):
+    def _execute_insert_multi(self, conn, keys: list[str], data_iter):
         """
         Alternative to _execute_insert for DBs support multivalue INSERT.
 
@@ -918,7 +916,7 @@ def insert_data(self):
 
         return column_names, data_list
 
-    def insert(self, chunksize: Optional[int] = None, method: Optional[str] = None):
+    def insert(self, chunksize: int | None = None, method: str | None = None):
 
         # set insert method
         if method is None:
@@ -957,7 +955,7 @@ def insert(self, chunksize: Optional[int] = None, method: Optional[str] = None):
     def _query_iterator(
         self,
         result,
-        chunksize: Optional[str],
+        chunksize: str | None,
         columns,
         coerce_float: bool = True,
         parse_dates=None,
@@ -1276,7 +1274,7 @@ def to_sql(
         index_label=None,
         schema=None,
         chunksize=None,
-        dtype: Optional[DtypeArg] = None,
+        dtype: DtypeArg | None = None,
         method=None,
     ):
         raise ValueError(
@@ -1305,7 +1303,7 @@ class SQLDatabase(PandasSQL):
 
     """
 
-    def __init__(self, engine, schema: Optional[str] = None, meta=None):
+    def __init__(self, engine, schema: str | None = None, meta=None):
         self.connectable = engine
         if not meta:
             from sqlalchemy.schema import MetaData
@@ -1329,12 +1327,12 @@ def execute(self, *args, **kwargs):
     def read_table(
         self,
         table_name: str,
-        index_col: Optional[Union[str, Sequence[str]]] = None,
+        index_col: str | Sequence[str] | None = None,
         coerce_float: bool = True,
         parse_dates=None,
         columns=None,
-        schema: Optional[str] = None,
-        chunksize: Optional[int] = None,
+        schema: str | None = None,
+        chunksize: int | None = None,
     ):
         """
         Read SQL database table into a DataFrame.
@@ -1394,7 +1392,7 @@ def _query_iterator(
         index_col=None,
         coerce_float=True,
         parse_dates=None,
-        dtype: Optional[DtypeArg] = None,
+        dtype: DtypeArg | None = None,
     ):
         """Return generator through chunked result set"""
         has_read_data = False
@@ -1424,12 +1422,12 @@ def _query_iterator(
     def read_query(
         self,
         sql: str,
-        index_col: Optional[str] = None,
+        index_col: str | None = None,
         coerce_float: bool = True,
         parse_dates=None,
         params=None,
-        chunksize: Optional[int] = None,
-        dtype: Optional[DtypeArg] = None,
+        chunksize: int | None = None,
+        dtype: DtypeArg | None = None,
     ):
         """
         Read SQL query into a DataFrame.
@@ -1515,7 +1513,7 @@ def to_sql(
         index_label=None,
         schema=None,
         chunksize=None,
-        dtype: Optional[DtypeArg] = None,
+        dtype: DtypeArg | None = None,
         method=None,
     ):
         """
@@ -1629,7 +1627,7 @@ def to_sql(
     def tables(self):
         return self.meta.tables
 
-    def has_table(self, name: str, schema: Optional[str] = None):
+    def has_table(self, name: str, schema: str | None = None):
         if _gt14():
             import sqlalchemy as sa
 
@@ -1640,7 +1638,7 @@ def has_table(self, name: str, schema: Optional[str] = None):
                 self.connectable.dialect.has_table, name, schema or self.meta.schema
             )
 
-    def get_table(self, table_name: str, schema: Optional[str] = None):
+    def get_table(self, table_name: str, schema: str | None = None):
         schema = schema or self.meta.schema
         if schema:
             tbl = self.meta.tables.get(".".join([schema, table_name]))
@@ -1656,7 +1654,7 @@ def get_table(self, table_name: str, schema: Optional[str] = None):
 
         return tbl
 
-    def drop_table(self, table_name: str, schema: Optional[str] = None):
+    def drop_table(self, table_name: str, schema: str | None = None):
         schema = schema or self.meta.schema
         if self.has_table(table_name, schema):
             self.meta.reflect(only=[table_name], schema=schema)
@@ -1667,9 +1665,9 @@ def _create_sql_schema(
         self,
         frame: DataFrame,
         table_name: str,
-        keys: Optional[List[str]] = None,
-        dtype: Optional[DtypeArg] = None,
-        schema: Optional[str] = None,
+        keys: list[str] | None = None,
+        dtype: DtypeArg | None = None,
+        schema: str | None = None,
     ):
         table = SQLTable(
             table_name,
@@ -1928,7 +1926,7 @@ def _query_iterator(
         index_col=None,
         coerce_float: bool = True,
         parse_dates=None,
-        dtype: Optional[DtypeArg] = None,
+        dtype: DtypeArg | None = None,
     ):
         """Return generator through chunked result set"""
         has_read_data = False
@@ -1961,8 +1959,8 @@ def read_query(
         coerce_float: bool = True,
         params=None,
         parse_dates=None,
-        chunksize: Optional[int] = None,
-        dtype: Optional[DtypeArg] = None,
+        chunksize: int | None = None,
+        dtype: DtypeArg | None = None,
     ):
 
         args = _convert_params(sql, params)
@@ -2008,7 +2006,7 @@ def to_sql(
         index_label=None,
         schema=None,
         chunksize=None,
-        dtype: Optional[DtypeArg] = None,
+        dtype: DtypeArg | None = None,
         method=None,
     ):
         """
@@ -2079,7 +2077,7 @@ def to_sql(
         table.create()
         table.insert(chunksize, method)
 
-    def has_table(self, name: str, schema: Optional[str] = None):
+    def has_table(self, name: str, schema: str | None = None):
         # TODO(wesm): unused?
         # escape = _get_valid_sqlite_name
         # esc_name = escape(name)
@@ -2089,10 +2087,10 @@ def has_table(self, name: str, schema: Optional[str] = None):
 
         return len(self.execute(query, [name]).fetchall()) > 0
 
-    def get_table(self, table_name: str, schema: Optional[str] = None):
+    def get_table(self, table_name: str, schema: str | None = None):
         return None  # not supported in fallback mode
 
-    def drop_table(self, name: str, schema: Optional[str] = None):
+    def drop_table(self, name: str, schema: str | None = None):
         drop_sql = f"DROP TABLE {_get_valid_sqlite_name(name)}"
         self.execute(drop_sql)
 
@@ -2101,8 +2099,8 @@ def _create_sql_schema(
         frame,
         table_name: str,
         keys=None,
-        dtype: Optional[DtypeArg] = None,
-        schema: Optional[str] = None,
+        dtype: DtypeArg | None = None,
+        schema: str | None = None,
     ):
         table = SQLiteTable(
             table_name,
@@ -2121,8 +2119,8 @@ def get_schema(
     name: str,
     keys=None,
     con=None,
-    dtype: Optional[DtypeArg] = None,
-    schema: Optional[str] = None,
+    dtype: DtypeArg | None = None,
+    schema: str | None = None,
 ):
     """
     Get the SQL db table schema for the given frame.
diff --git a/pandas/io/xml.py b/pandas/io/xml.py
index abbfe7657624f..8b0055a522e25 100644
--- a/pandas/io/xml.py
+++ b/pandas/io/xml.py
@@ -2,13 +2,9 @@
 :mod:`pandas.io.xml` is a module for reading XML.
 """
 
+from __future__ import annotations
+
 import io
-from typing import (
-    Dict,
-    List,
-    Optional,
-    Union,
-)
 
 from pandas._typing import (
     Buffer,
@@ -124,7 +120,7 @@ def __init__(
         self.compression = compression
         self.storage_options = storage_options
 
-    def parse_data(self) -> List[Dict[str, Optional[str]]]:
+    def parse_data(self) -> list[dict[str, str | None]]:
         """
         Parse xml data.
 
@@ -134,7 +130,7 @@ def parse_data(self) -> List[Dict[str, Optional[str]]]:
 
         raise AbstractMethodError(self)
 
-    def _parse_nodes(self) -> List[Dict[str, Optional[str]]]:
+    def _parse_nodes(self) -> list[dict[str, str | None]]:
         """
         Parse xml nodes.
 
@@ -206,7 +202,7 @@ class _EtreeFrameParser(_XMLFrameParser):
     def __init__(self, *args, **kwargs) -> None:
         super().__init__(*args, **kwargs)
 
-    def parse_data(self) -> List[Dict[str, Optional[str]]]:
+    def parse_data(self) -> list[dict[str, str | None]]:
         from xml.etree.ElementTree import XML
 
         if self.stylesheet is not None:
@@ -221,9 +217,9 @@ def parse_data(self) -> List[Dict[str, Optional[str]]]:
 
         return self._parse_nodes()
 
-    def _parse_nodes(self) -> List[Dict[str, Optional[str]]]:
+    def _parse_nodes(self) -> list[dict[str, str | None]]:
         elems = self.xml_doc.findall(self.xpath, namespaces=self.namespaces)
-        dicts: List[Dict[str, Optional[str]]]
+        dicts: list[dict[str, str | None]]
 
         if self.elems_only and self.attrs_only:
             raise ValueError("Either element or attributes can be parsed not both.")
@@ -382,7 +378,7 @@ class _LxmlFrameParser(_XMLFrameParser):
     def __init__(self, *args, **kwargs) -> None:
         super().__init__(*args, **kwargs)
 
-    def parse_data(self) -> List[Dict[str, Optional[str]]]:
+    def parse_data(self) -> list[dict[str, str | None]]:
         """
         Parse xml data.
 
@@ -403,9 +399,9 @@ def parse_data(self) -> List[Dict[str, Optional[str]]]:
 
         return self._parse_nodes()
 
-    def _parse_nodes(self) -> List[Dict[str, Optional[str]]]:
+    def _parse_nodes(self) -> list[dict[str, str | None]]:
         elems = self.xml_doc.xpath(self.xpath, namespaces=self.namespaces)
-        dicts: List[Dict[str, Optional[str]]]
+        dicts: list[dict[str, str | None]]
 
         if self.elems_only and self.attrs_only:
             raise ValueError("Either element or attributes can be parsed not both.")
@@ -583,7 +579,7 @@ def get_data_from_filepath(
     encoding,
     compression,
     storage_options,
-) -> Union[str, bytes, Buffer]:
+) -> str | bytes | Buffer:
     """
     Extract raw XML data.
 
@@ -622,7 +618,7 @@ def get_data_from_filepath(
     return filepath_or_buffer
 
 
-def preprocess_data(data) -> Union[io.StringIO, io.BytesIO]:
+def preprocess_data(data) -> io.StringIO | io.BytesIO:
     """
     Convert extracted raw data.
 
@@ -694,7 +690,7 @@ def _parse(
 
     lxml = import_optional_dependency("lxml.etree", errors="ignore")
 
-    p: Union[_EtreeFrameParser, _LxmlFrameParser]
+    p: _EtreeFrameParser | _LxmlFrameParser
 
     if parser == "lxml":
         if lxml is not None:
@@ -737,14 +733,14 @@ def _parse(
 @doc(storage_options=_shared_docs["storage_options"])
 def read_xml(
     path_or_buffer: FilePathOrBuffer,
-    xpath: Optional[str] = "./*",
-    namespaces: Optional[Union[dict, List[dict]]] = None,
-    elems_only: Optional[bool] = False,
-    attrs_only: Optional[bool] = False,
-    names: Optional[List[str]] = None,
-    encoding: Optional[str] = "utf-8",
-    parser: Optional[str] = "lxml",
-    stylesheet: Optional[FilePathOrBuffer] = None,
+    xpath: str | None = "./*",
+    namespaces: dict | list[dict] | None = None,
+    elems_only: bool | None = False,
+    attrs_only: bool | None = False,
+    names: list[str] | None = None,
+    encoding: str | None = "utf-8",
+    parser: str | None = "lxml",
+    stylesheet: FilePathOrBuffer | None = None,
     compression: CompressionOptions = "infer",
     storage_options: StorageOptions = None,
 ) -> DataFrame:
diff --git a/pandas/tseries/frequencies.py b/pandas/tseries/frequencies.py
index 05b8885b7d9b7..c55ac6ce228bf 100644
--- a/pandas/tseries/frequencies.py
+++ b/pandas/tseries/frequencies.py
@@ -1,4 +1,5 @@
-from typing import Optional
+from __future__ import annotations
+
 import warnings
 
 import numpy as np
@@ -93,7 +94,7 @@
     _offset_to_period_map[f"W-{_d}"] = f"W-{_d}"
 
 
-def get_period_alias(offset_str: str) -> Optional[str]:
+def get_period_alias(offset_str: str) -> str | None:
     """
     Alias to closest period strings BQ->Q etc.
     """
@@ -123,7 +124,7 @@ def get_offset(name: str) -> DateOffset:
 # Period codes
 
 
-def infer_freq(index, warn: bool = True) -> Optional[str]:
+def infer_freq(index, warn: bool = True) -> str | None:
     """
     Infer the most likely frequency given the input index. If the frequency is
     uncertain, a warning will be printed.
@@ -239,7 +240,7 @@ def is_unique(self) -> bool:
     def is_unique_asi8(self) -> bool:
         return len(self.deltas_asi8) == 1
 
-    def get_freq(self) -> Optional[str]:
+    def get_freq(self) -> str | None:
         """
         Find the appropriate frequency string to describe the inferred
         frequency of self.i8values
@@ -313,7 +314,7 @@ def mdiffs(self):
     def ydiffs(self):
         return unique_deltas(self.fields["Y"].astype("i8"))
 
-    def _infer_daily_rule(self) -> Optional[str]:
+    def _infer_daily_rule(self) -> str | None:
         annual_rule = self._get_annual_rule()
         if annual_rule:
             nyears = self.ydiffs[0]
@@ -345,7 +346,7 @@ def _infer_daily_rule(self) -> Optional[str]:
 
         return None
 
-    def _get_daily_rule(self) -> Optional[str]:
+    def _get_daily_rule(self) -> str | None:
         days = self.deltas[0] / _ONE_DAY
         if days % 7 == 0:
             # Weekly
@@ -355,7 +356,7 @@ def _get_daily_rule(self) -> Optional[str]:
         else:
             return _maybe_add_count("D", days)
 
-    def _get_annual_rule(self) -> Optional[str]:
+    def _get_annual_rule(self) -> str | None:
         if len(self.ydiffs) > 1:
             return None
 
@@ -365,7 +366,7 @@ def _get_annual_rule(self) -> Optional[str]:
         pos_check = self.month_position_check()
         return {"cs": "AS", "bs": "BAS", "ce": "A", "be": "BA"}.get(pos_check)
 
-    def _get_quarterly_rule(self) -> Optional[str]:
+    def _get_quarterly_rule(self) -> str | None:
         if len(self.mdiffs) > 1:
             return None
 
@@ -375,7 +376,7 @@ def _get_quarterly_rule(self) -> Optional[str]:
         pos_check = self.month_position_check()
         return {"cs": "QS", "bs": "BQS", "ce": "Q", "be": "BQ"}.get(pos_check)
 
-    def _get_monthly_rule(self) -> Optional[str]:
+    def _get_monthly_rule(self) -> str | None:
         if len(self.mdiffs) > 1:
             return None
         pos_check = self.month_position_check()
@@ -397,7 +398,7 @@ def _is_business_daily(self) -> bool:
             | ((weekdays > 0) & (weekdays <= 4) & (shifts == 1))
         )
 
-    def _get_wom_rule(self) -> Optional[str]:
+    def _get_wom_rule(self) -> str | None:
         # FIXME: dont leave commented-out
         #         wdiffs = unique(np.diff(self.index.week))
         # We also need -47, -49, -48 to catch index spanning year boundary
diff --git a/pandas/tseries/holiday.py b/pandas/tseries/holiday.py
index ce303928dc8ee..54ac116afe3cf 100644
--- a/pandas/tseries/holiday.py
+++ b/pandas/tseries/holiday.py
@@ -1,8 +1,9 @@
+from __future__ import annotations
+
 from datetime import (
     datetime,
     timedelta,
 )
-from typing import List
 import warnings
 
 from dateutil.relativedelta import (  # noqa
@@ -384,7 +385,7 @@ class AbstractHolidayCalendar(metaclass=HolidayCalendarMetaClass):
     Abstract interface to create holidays following certain rules.
     """
 
-    rules: List[Holiday] = []
+    rules: list[Holiday] = []
     start_date = Timestamp(datetime(1970, 1, 1))
     end_date = Timestamp(datetime(2200, 12, 31))
     _cache = None
diff --git a/pandas/util/_decorators.py b/pandas/util/_decorators.py
index ffc0255ca9de7..835001b3e1829 100644
--- a/pandas/util/_decorators.py
+++ b/pandas/util/_decorators.py
@@ -1,15 +1,12 @@
+from __future__ import annotations
+
 from functools import wraps
 import inspect
 from textwrap import dedent
 from typing import (
     Any,
     Callable,
-    List,
     Mapping,
-    Optional,
-    Tuple,
-    Type,
-    Union,
     cast,
 )
 import warnings
@@ -22,10 +19,10 @@ def deprecate(
     name: str,
     alternative: Callable[..., Any],
     version: str,
-    alt_name: Optional[str] = None,
-    klass: Optional[Type[Warning]] = None,
+    alt_name: str | None = None,
+    klass: type[Warning] | None = None,
     stacklevel: int = 2,
-    msg: Optional[str] = None,
+    msg: str | None = None,
 ) -> Callable[[F], F]:
     """
     Return a new function that emits a deprecation warning on use.
@@ -95,8 +92,8 @@ def wrapper(*args, **kwargs) -> Callable[..., Any]:
 
 def deprecate_kwarg(
     old_arg_name: str,
-    new_arg_name: Optional[str],
-    mapping: Optional[Union[Mapping[Any, Any], Callable[[Any], Any]]] = None,
+    new_arg_name: str | None,
+    mapping: Mapping[Any, Any] | Callable[[Any], Any] | None = None,
     stacklevel: int = 2,
 ) -> Callable[[F], F]:
     """
@@ -214,7 +211,7 @@ def wrapper(*args, **kwargs) -> Callable[..., Any]:
     return _deprecate_kwarg
 
 
-def _format_argument_list(allow_args: Union[List[str], int]):
+def _format_argument_list(allow_args: list[str] | int):
     """
     Convert the allow_args argument (either string or integer) of
     `deprecate_nonkeyword_arguments` function to a string describing
@@ -259,7 +256,7 @@ def _format_argument_list(allow_args: Union[List[str], int]):
 
 def deprecate_nonkeyword_arguments(
     version: str,
-    allowed_args: Optional[Union[List[str], int]] = None,
+    allowed_args: list[str] | int | None = None,
     stacklevel: int = 2,
 ) -> Callable:
     """
@@ -315,7 +312,7 @@ def wrapper(*args, **kwargs):
 
 
 def rewrite_axis_style_signature(
-    name: str, extra_params: List[Tuple[str, Any]]
+    name: str, extra_params: list[tuple[str, Any]]
 ) -> Callable[..., Any]:
     def decorate(func: F) -> F:
         @wraps(func)
@@ -344,7 +341,7 @@ def wrapper(*args, **kwargs) -> Callable[..., Any]:
     return decorate
 
 
-def doc(*docstrings: Union[str, Callable], **params) -> Callable[[F], F]:
+def doc(*docstrings: str | Callable, **params) -> Callable[[F], F]:
     """
     A decorator take docstring templates, concatenate them and perform string
     substitution on it.
@@ -366,7 +363,7 @@ def doc(*docstrings: Union[str, Callable], **params) -> Callable[[F], F]:
 
     def decorator(decorated: F) -> F:
         # collecting docstring and docstring templates
-        docstring_components: List[Union[str, Callable]] = []
+        docstring_components: list[str | Callable] = []
         if decorated.__doc__:
             docstring_components.append(dedent(decorated.__doc__))
 
@@ -472,9 +469,9 @@ def my_dog(has='fleas'):
         pass
     """
 
-    addendum: Optional[str]
+    addendum: str | None
 
-    def __init__(self, addendum: Optional[str], join: str = "", indents: int = 0):
+    def __init__(self, addendum: str | None, join: str = "", indents: int = 0):
         if indents > 0:
             self.addendum = indent(addendum, indents=indents)
         else:
@@ -489,7 +486,7 @@ def __call__(self, func: F) -> F:
         return func
 
 
-def indent(text: Optional[str], indents: int = 1) -> str:
+def indent(text: str | None, indents: int = 1) -> str:
     if not text or not isinstance(text, str):
         return ""
     jointext = "".join(["\n"] + ["    "] * indents)
diff --git a/pandas/util/_doctools.py b/pandas/util/_doctools.py
index d6689fcb8cd01..0d90d9b2871d9 100644
--- a/pandas/util/_doctools.py
+++ b/pandas/util/_doctools.py
@@ -1,7 +1,4 @@
-from typing import (
-    Optional,
-    Tuple,
-)
+from __future__ import annotations
 
 import numpy as np
 
@@ -24,14 +21,14 @@ def __init__(
         self.cell_height = cell_height
         self.font_size = font_size
 
-    def _shape(self, df: pd.DataFrame) -> Tuple[int, int]:
+    def _shape(self, df: pd.DataFrame) -> tuple[int, int]:
         """
         Calculate table shape considering index levels.
         """
         row, col = df.shape
         return row + df.columns.nlevels, col + df.index.nlevels
 
-    def _get_cells(self, left, right, vertical) -> Tuple[int, int]:
+    def _get_cells(self, left, right, vertical) -> tuple[int, int]:
         """
         Calculate appropriate figure size based on left and right data.
         """
@@ -137,7 +134,7 @@ def _insert_index(self, data):
             data.columns = col
         return data
 
-    def _make_table(self, ax, df, title: str, height: Optional[float] = None):
+    def _make_table(self, ax, df, title: str, height: float | None = None):
         if df is None:
             ax.set_visible(False)
             return
diff --git a/pandas/util/_exceptions.py b/pandas/util/_exceptions.py
index e70c185628f71..9a6c62df76ef2 100644
--- a/pandas/util/_exceptions.py
+++ b/pandas/util/_exceptions.py
@@ -1,6 +1,7 @@
+from __future__ import annotations
+
 import contextlib
 import inspect
-from typing import Tuple
 
 
 @contextlib.contextmanager
@@ -15,7 +16,7 @@ def rewrite_exception(old_name: str, new_name: str):
             raise
         msg = str(err.args[0])
         msg = msg.replace(old_name, new_name)
-        args: Tuple[str, ...] = (msg,)
+        args: tuple[str, ...] = (msg,)
         if len(err.args) > 1:
             args = args + err.args[1:]
         err.args = args
diff --git a/pandas/util/_print_versions.py b/pandas/util/_print_versions.py
index cf5af0de5d3b5..6c180f68395db 100644
--- a/pandas/util/_print_versions.py
+++ b/pandas/util/_print_versions.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import codecs
 import json
 import locale
@@ -5,11 +7,6 @@
 import platform
 import struct
 import sys
-from typing import (
-    Dict,
-    Optional,
-    Union,
-)
 
 from pandas._typing import JSONSerializable
 from pandas.compat._optional import (
@@ -19,7 +16,7 @@
 )
 
 
-def _get_commit_hash() -> Optional[str]:
+def _get_commit_hash() -> str | None:
     """
     Use vendored versioneer code to get git hash, which handles
     git worktree correctly.
@@ -30,7 +27,7 @@ def _get_commit_hash() -> Optional[str]:
     return versions["full-revisionid"]
 
 
-def _get_sys_info() -> Dict[str, JSONSerializable]:
+def _get_sys_info() -> dict[str, JSONSerializable]:
     """
     Returns system information as a JSON serializable dictionary.
     """
@@ -52,7 +49,7 @@ def _get_sys_info() -> Dict[str, JSONSerializable]:
     }
 
 
-def _get_dependency_info() -> Dict[str, JSONSerializable]:
+def _get_dependency_info() -> dict[str, JSONSerializable]:
     """
     Returns dependency information as a JSON serializable dictionary.
     """
@@ -86,14 +83,14 @@ def _get_dependency_info() -> Dict[str, JSONSerializable]:
     ]
     deps.extend(list(VERSIONS))
 
-    result: Dict[str, JSONSerializable] = {}
+    result: dict[str, JSONSerializable] = {}
     for modname in deps:
         mod = import_optional_dependency(modname, errors="ignore")
         result[modname] = get_version(mod) if mod else None
     return result
 
 
-def show_versions(as_json: Union[str, bool] = False) -> None:
+def show_versions(as_json: str | bool = False) -> None:
     """
     Provide useful information, important for bug reports.
 
diff --git a/pandas/util/_test_decorators.py b/pandas/util/_test_decorators.py
index 752ed43849d2b..dd22b5ef5e4ac 100644
--- a/pandas/util/_test_decorators.py
+++ b/pandas/util/_test_decorators.py
@@ -23,13 +23,12 @@ def test_foo():
 
 For more information, refer to the ``pytest`` documentation on ``skipif``.
 """
+from __future__ import annotations
+
 from contextlib import contextmanager
 from distutils.version import LooseVersion
 import locale
-from typing import (
-    Callable,
-    Optional,
-)
+from typing import Callable
 import warnings
 
 import numpy as np
@@ -49,7 +48,7 @@ def test_foo():
 )
 
 
-def safe_import(mod_name: str, min_version: Optional[str] = None):
+def safe_import(mod_name: str, min_version: str | None = None):
     """
     Parameters
     ----------
@@ -144,7 +143,7 @@ def skip_if_installed(package: str):
 
 # TODO: return type, _pytest.mark.structures.MarkDecorator is not public
 # https://github.com/pytest-dev/pytest/issues/7469
-def skip_if_no(package: str, min_version: Optional[str] = None):
+def skip_if_no(package: str, min_version: str | None = None):
     """
     Generic function to help skip tests when required packages are not
     present on the testing system.
@@ -208,7 +207,7 @@ def skip_if_no(package: str, min_version: Optional[str] = None):
 
 # TODO: return type, _pytest.mark.structures.MarkDecorator is not public
 # https://github.com/pytest-dev/pytest/issues/7469
-def skip_if_np_lt(ver_str: str, *args, reason: Optional[str] = None):
+def skip_if_np_lt(ver_str: str, *args, reason: str | None = None):
     if reason is None:
         reason = f"NumPy {ver_str} or greater required"
     return pytest.mark.skipif(
diff --git a/pandas/util/_validators.py b/pandas/util/_validators.py
index 087dccfadcce1..d5d5439ecb8eb 100644
--- a/pandas/util/_validators.py
+++ b/pandas/util/_validators.py
@@ -2,10 +2,11 @@
 Module that contains many useful utilities
 for validating data or function arguments
 """
+from __future__ import annotations
+
 from typing import (
     Iterable,
     Sequence,
-    Union,
 )
 import warnings
 
@@ -383,7 +384,7 @@ def validate_fillna_kwargs(value, method, validate_scalar_dict_value=True):
     return value, method
 
 
-def validate_percentile(q: Union[float, Iterable[float]]) -> np.ndarray:
+def validate_percentile(q: float | Iterable[float]) -> np.ndarray:
     """
     Validate percentiles (used by describe and quantile).
 
@@ -418,7 +419,7 @@ def validate_percentile(q: Union[float, Iterable[float]]) -> np.ndarray:
 
 
 def validate_ascending(
-    ascending: Union[Union[bool, int], Sequence[Union[bool, int]]] = True,
+    ascending: bool | int | Sequence[bool | int] = True,
 ):
     """Validate ``ascending`` kwargs for ``sort_index`` method."""
     kwargs = {"none_allowed": False, "int_allowed": True}