diff --git a/Misc/NEWS.d/next/Library/2023-09-24-16-43-33.gh-issue-109782.gMC_7z.rst b/Misc/NEWS.d/next/Library/2023-09-24-16-43-33.gh-issue-109782.gMC_7z.rst
new file mode 100644
index 00000000000000..7612e59dc45412
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-09-24-16-43-33.gh-issue-109782.gMC_7z.rst
@@ -0,0 +1,2 @@
+Ensure the signature of :func:`os.path.isdir` is identical on all platforms.
+Patch by Amin Alaee.
diff --git a/Modules/clinic/posixmodule.c.h b/Modules/clinic/posixmodule.c.h
index 5924c4ab03943a..fb01c8dbc8d81c 100644
--- a/Modules/clinic/posixmodule.c.h
+++ b/Modules/clinic/posixmodule.c.h
@@ -1975,7 +1975,7 @@ os__path_splitroot(PyObject *module, PyObject *const *args, Py_ssize_t nargs, Py
 #if defined(MS_WINDOWS)
 
 PyDoc_STRVAR(os__path_isdir__doc__,
-"_path_isdir($module, /, path)\n"
+"_path_isdir($module, /, s)\n"
 "--\n"
 "\n"
 "Return true if the pathname refers to an existing directory.");
@@ -1984,7 +1984,7 @@ PyDoc_STRVAR(os__path_isdir__doc__,
     {"_path_isdir", _PyCFunction_CAST(os__path_isdir), METH_FASTCALL|METH_KEYWORDS, os__path_isdir__doc__},
 
 static PyObject *
-os__path_isdir_impl(PyObject *module, PyObject *path);
+os__path_isdir_impl(PyObject *module, PyObject *s);
 
 static PyObject *
 os__path_isdir(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
@@ -1999,7 +1999,7 @@ os__path_isdir(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
         PyObject *ob_item[NUM_KEYWORDS];
     } _kwtuple = {
         .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
-        .ob_item = { &_Py_ID(path), },
+        .ob_item = { &_Py_ID(s), },
     };
     #undef NUM_KEYWORDS
     #define KWTUPLE (&_kwtuple.ob_base.ob_base)
@@ -2008,7 +2008,7 @@ os__path_isdir(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
     #  define KWTUPLE NULL
     #endif  // !Py_BUILD_CORE
 
-    static const char * const _keywords[] = {"path", NULL};
+    static const char * const _keywords[] = {"s", NULL};
     static _PyArg_Parser _parser = {
         .keywords = _keywords,
         .fname = "_path_isdir",
@@ -2016,14 +2016,14 @@ os__path_isdir(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObje
     };
     #undef KWTUPLE
     PyObject *argsbuf[1];
-    PyObject *path;
+    PyObject *s;
 
     args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
     if (!args) {
         goto exit;
     }
-    path = args[0];
-    return_value = os__path_isdir_impl(module, path);
+    s = args[0];
+    return_value = os__path_isdir_impl(module, s);
 
 exit:
     return return_value;
@@ -11999,4 +11999,4 @@ os_waitstatus_to_exitcode(PyObject *module, PyObject *const *args, Py_ssize_t na
 #ifndef OS_WAITSTATUS_TO_EXITCODE_METHODDEF
     #define OS_WAITSTATUS_TO_EXITCODE_METHODDEF
 #endif /* !defined(OS_WAITSTATUS_TO_EXITCODE_METHODDEF) */
-/*[clinic end generated code: output=6646be70849f971f input=a9049054013a1b77]*/
+/*[clinic end generated code: output=ce77253f8879f36e input=a9049054013a1b77]*/
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 816601da488d62..b33293992f0d8e 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -4901,25 +4901,25 @@ os__path_splitroot_impl(PyObject *module, path_t *path)
 /*[clinic input]
 os._path_isdir
 
-    path: 'O'
+    s: 'O'
 
 Return true if the pathname refers to an existing directory.
 
 [clinic start generated code]*/
 
 static PyObject *
-os__path_isdir_impl(PyObject *module, PyObject *path)
-/*[clinic end generated code: output=00faea0af309669d input=b1d2571cf7291aaf]*/
+os__path_isdir_impl(PyObject *module, PyObject *s)
+/*[clinic end generated code: output=9d87ab3c8b8a4e61 input=c17f7ef21d22d64e]*/
 {
     HANDLE hfile;
     BOOL close_file = TRUE;
     FILE_BASIC_INFO info;
-    path_t _path = PATH_T_INITIALIZE("isdir", "path", 0, 1);
+    path_t _path = PATH_T_INITIALIZE("isdir", "s", 0, 1);
     int result;
     BOOL slow_path = TRUE;
     FILE_STAT_BASIC_INFORMATION statInfo;
 
-    if (!path_converter(path, &_path)) {
+    if (!path_converter(s, &_path)) {
         path_cleanup(&_path);
         if (PyErr_ExceptionMatches(PyExc_ValueError)) {
             PyErr_Clear();