diff --git a/lib/fontv/utilities.py b/lib/fontv/utilities.py
index bd6bb7a..6375d10 100644
--- a/lib/fontv/utilities.py
+++ b/lib/fontv/utilities.py
@@ -10,6 +10,8 @@
 
 import os
 
+import git.repo.fun
+
 
 def dir_exists(dirpath):
     """Tests for existence of a directory on the string filepath"""
@@ -39,13 +41,26 @@ def get_git_root_path(filepath):
     :raises: IOError if unable to detect the root of the git repository through this path traversal
     """
 
+    if "GIT_DIR" in os.environ:
+        dot_git = os.path.abspath(os.environ["GIT_DIR"])
+        if git.repo.fun.is_git_dir(dot_git):
+            return os.path.dirname(dot_git)
+
     # begin by defining directory that contains font as the git root needle
     gitroot_path = os.path.dirname(os.path.abspath(filepath))
 
     # search up to five directories above for the git repo root
     for _ in range(6):
-        if dir_exists(os.path.join(gitroot_path, ".git")):
+        dot_git = os.path.join(gitroot_path, ".git")
+        if git.repo.fun.is_git_dir(dot_git):
             return gitroot_path
+        elif file_exists(dot_git):
+            # Returns something like ".../font-v/.git/worktrees/work-worktrees-work"
+            worktree_path = git.repo.fun.find_worktree_git_dir(dot_git)
+            if worktree_path:
+                # ".../font-v/.git/worktrees/work-worktrees-work" -> ".../font-v"
+                return worktree_path.split("/.git/worktrees/", 2)[0]
+
         gitroot_path = os.path.dirname(gitroot_path)
 
     raise IOError(
diff --git a/tests/test_utilities.py b/tests/test_utilities.py
index 089b5e1..26448fd 100644
--- a/tests/test_utilities.py
+++ b/tests/test_utilities.py
@@ -2,6 +2,7 @@
 # -*- coding: utf-8 -*-
 
 import os
+import subprocess
 
 import pytest
 
@@ -56,12 +57,45 @@ def test_utilities_get_gitrootpath_function_returns_proper_path_three_levels_up(
     assert os.path.isdir(gitdir_path) is True
 
 
+@pytest.fixture
+def worktree_fixture():
+    subprocess.check_call(
+        ["git", "worktree", "add", "--detach", "/tmp/font-v", "HEAD^"]
+    )
+    yield
+    subprocess.call(
+        [
+            "git",
+            "worktree",
+            "remove",
+            "/tmp/font-v",
+        ]
+    )
+
+
+def test_utilities_get_gitrootpath_function_returns_proper_path_from_worktree(
+    worktree_fixture,
+):
+    filepath = "/tmp/font-v/README.md"
+    gitdir_path = get_git_root_path(filepath)
+    assert os.path.basename(gitdir_path) == "font-v"
+    assert os.path.isdir(gitdir_path) is True
+
+
 def test_utilities_get_gitrootpath_function_raises_ioerror_six_levels_up():
     with pytest.raises(IOError):
         filepath = "tests/testfiles/deepdir/deepdir2/deepdir3/deepdir4/test.txt"
         get_git_root_path(filepath)
 
 
+def test_utilities_get_gitrootpath_uses_git_dir_env_var():
+    os.environ["GIT_DIR"] = os.path.abspath(".git")
+    filepath = "/this/isnt/even/a/path/but/it/doesnt/matter"
+    gitdir_path = get_git_root_path(filepath)
+    assert os.path.basename(gitdir_path) == "font-v"
+    assert os.path.isdir(gitdir_path) is True
+
+
 def test_utilities_is_font_ttf():
     assert is_font("Test-Regular.ttf") is True