diff --git a/cpplint.py b/cpplint.py
index 3fde105..f74eff7 100755
--- a/cpplint.py
+++ b/cpplint.py
@@ -6079,7 +6079,7 @@
       try:
           _valid_extensions = set(val.split(','))
       except ValueError:
-          PrintUsage('Extensions must be comma seperated list.')
+          PrintUsage('Extensions must be comma separated list.')
 
   if not filenames:
     PrintUsage('No files were specified.')