diff --git a/.pre-commit-hooks.yaml b/.pre-commit-hooks.yaml
index f8523d4..0caa87e 100644
--- a/.pre-commit-hooks.yaml
+++ b/.pre-commit-hooks.yaml
@@ -95,6 +95,12 @@
     entry: check-yaml
     language: python
     types: [yaml]
+-   id: check-yaml-filename-extension
+    name: check yaml filename extension
+    description: checks that yaml file names ends with specified extension.
+    entry: check-yaml-filename-extension
+    language: python
+    types: [yaml]
 -   id: debug-statements
     name: debug statements (python)
     description: checks for debugger imports and py37+ `breakpoint()` calls in python source.
diff --git a/README.md b/README.md
index 6dcbf0d..cd37ea2 100644
--- a/README.md
+++ b/README.md
@@ -88,6 +88,10 @@ Attempts to load all yaml files to verify syntax.
     portability to other yaml implementations.
     Implies `--allow-multiple-documents`.
 
+#### `check-yaml-filename-extension`
+Ensures that yaml file names ends with a specified extension.
+  - `--extension` - Specifies which extension to use `yaml` or `yml`. Defaults to `yaml`.
+
 #### `debug-statements`
 Check for debugger imports and py37+ `breakpoint()` calls in python source.
 
diff --git a/pre_commit_hooks/check_yaml_filename_extension.py b/pre_commit_hooks/check_yaml_filename_extension.py
new file mode 100644
index 0000000..5e0bd9e
--- /dev/null
+++ b/pre_commit_hooks/check_yaml_filename_extension.py
@@ -0,0 +1,29 @@
+from __future__ import annotations
+
+import argparse
+import os
+from typing import Sequence
+
+from pre_commit_hooks.util import cmd_output
+
+
+def main(argv: Sequence[str] | None = None) -> int:
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--extension', choices=['yaml', 'yml'], default='yaml')
+    parser.add_argument('filenames', nargs='*', help='Filenames to check.')
+
+    args = parser.parse_args(argv)
+    extension = f'.{args.extension}'
+
+    retval = 0
+    for filename in args.filenames:
+        if not filename.endswith(extension):
+            new_filename = f'{os.path.splitext(filename)[0]}{extension}'
+            cmd_output('git', 'mv', filename, new_filename)
+            retval = 1
+
+    return retval
+
+
+if __name__ == '__main__':
+    raise SystemExit(main())
diff --git a/setup.cfg b/setup.cfg
index d4658e2..b3f8751 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -45,6 +45,7 @@ console_scripts =
     check-vcs-permalinks = pre_commit_hooks.check_vcs_permalinks:main
     check-xml = pre_commit_hooks.check_xml:main
     check-yaml = pre_commit_hooks.check_yaml:main
+    check-yaml-filename-extension = pre_commit_hooks.check_yaml_filename_extension:main
     debug-statement-hook = pre_commit_hooks.debug_statement_hook:main
     destroyed-symlinks = pre_commit_hooks.destroyed_symlinks:main
     detect-aws-credentials = pre_commit_hooks.detect_aws_credentials:main
diff --git a/tests/check_yaml_filename_extension_test.py b/tests/check_yaml_filename_extension_test.py
new file mode 100644
index 0000000..afbcbd9
--- /dev/null
+++ b/tests/check_yaml_filename_extension_test.py
@@ -0,0 +1,26 @@
+from __future__ import annotations
+
+import pytest
+
+from pre_commit_hooks.check_yaml_filename_extension import main
+from pre_commit_hooks.util import cmd_output
+
+
+@pytest.mark.parametrize(
+    ('filename', 'new_filename', 'expected_retval'), (
+        ('file_1.yml', 'file_1.yaml', 1),
+        ('.file_2.yml', '.file_2.yaml', 1),
+        ('file_3.yaml', 'file_3.yaml', 0),
+    ),
+)
+def test_main(temp_git_dir, filename, new_filename, expected_retval):
+    with temp_git_dir.as_cwd():
+        temp_git_dir.join(filename).write('---')
+        cmd_output('git', 'add', filename)
+
+        retv = main([filename])
+
+        assert retv == expected_retval
+        assert temp_git_dir.join(new_filename).exists()
+
+        assert retv == 0 or not temp_git_dir.join(filename).exists()