diff --git a/sphinx/ext/autodoc/__init__.py b/sphinx/ext/autodoc/__init__.py
index 43e5dc616..bcc9d6a7e 100644
--- a/sphinx/ext/autodoc/__init__.py
+++ b/sphinx/ext/autodoc/__init__.py
@@ -14,6 +14,7 @@
 import inspect
 import re
 import sys
+import warnings
 from typing import Any
 
 from docutils.statemachine import ViewList