diff --git a/Lib/os.py b/Lib/os.py
index 84722af9862..d6ebf4b78f9 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -1,4 +1,4 @@
-"""OS routines for Mac, DOS, NT, or Posix depending on what system we're on.
+r"""OS routines for Mac, DOS, NT, or Posix depending on what system we're on.
 
 This exports:
   - all functions from posix, nt, dos, os2, mac, or ce, e.g. unlink, stat, etc.