diff --git a/Lib/unittest/case.py b/Lib/unittest/case.py
index b609caf..85ff002 100644
--- a/Lib/unittest/case.py
+++ b/Lib/unittest/case.py
@@ -160,7 +160,7 @@
 
     longMessage = False
 
-    # This attribute sets the maximum length of a diff in failure messsages
+    # This attribute sets the maximum length of a diff in failure messages
     # by assert methods using difflib. It is looked up as an instance attribute
     # so can be configured by individual tests if required.