diff --git a/sphinx/ext/inheritance_diagram.py b/sphinx/ext/inheritance_diagram.py
index b930d8cab..a12bad256 100644
--- a/sphinx/ext/inheritance_diagram.py
+++ b/sphinx/ext/inheritance_diagram.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-"""
+r"""
     sphinx.ext.inheritance_diagram
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~