diff --git a/infrahub_sdk/repository.py b/infrahub_sdk/repository.py
index 2ad2080a..5bcd1387 100644
--- a/infrahub_sdk/repository.py
+++ b/infrahub_sdk/repository.py
@@ -17,7 +17,8 @@ def initialize_repo(self) -> Repo:
 
         root_path = Path(self.root_directory)
 
-        if root_path.exists() and (root_path / ".git").is_dir():
+        if root_path.exists() and (root_path / ".git").exists():
+            # `.git` is a directory in a regular clone and a gitlink file in a worktree.
             repo = Repo(self.root_directory)  # Open existing repo
         else:
             repo = Repo.init(self.root_directory, default_branch=self.branch.encode("utf-8"))
diff --git a/tests/unit/sdk/test_repository.py b/tests/unit/sdk/test_repository.py
index 756b2e36..eca1c9a6 100644
--- a/tests/unit/sdk/test_repository.py
+++ b/tests/unit/sdk/test_repository.py
@@ -41,6 +41,26 @@ def test_initialize_repo_uses_existing_repo(temp_dir: str) -> None:
     assert (Path(temp_dir) / ".git").is_dir()
 
 
+def test_initialize_repo_uses_existing_repo_in_worktree(temp_dir: str) -> None:
+    """A git worktree has a `.git` file (gitlink), not a directory.
+
+    GitRepoManager must open the existing repo via the gitlink instead of trying
+    to re-initialize one, which would crash on `mkdir` because the file already exists.
+    """
+    main_path = Path(temp_dir) / "main"
+    worktree_path = Path(temp_dir) / "worktree"
+    main_path.mkdir()
+    worktree_path.mkdir()
+    Repo.init(str(main_path), default_branch=b"main")
+    (worktree_path / ".git").write_text(f"gitdir: {main_path}/.git\n")
+
+    manager = GitRepoManager(str(worktree_path))
+
+    assert manager.git is not None
+    assert isinstance(manager.git, Repo)
+    assert (worktree_path / ".git").is_file()
+
+
 def test_active_branch_returns_correct_branch(temp_dir: str) -> None:
     """Test that the active branch is correctly returned."""
     manager = GitRepoManager(temp_dir, branch="develop")