diff --git a/Lib/StringIO.py b/Lib/StringIO.py
index 870e97eb300..6422f76647c 100644
--- a/Lib/StringIO.py
+++ b/Lib/StringIO.py
@@ -1,4 +1,4 @@
-"""File-like objects that read from or write to a string buffer.
+r"""File-like objects that read from or write to a string buffer.
 
 This implements (nearly) all stdio methods.