diff --git a/googlemock/scripts/pump.py b/googlemock/scripts/pump.py
index 5523a19d..af9f3006 100755
--- a/googlemock/scripts/pump.py
+++ b/googlemock/scripts/pump.py
@@ -843,7 +843,7 @@ def main(argv):
   if output_file_path == '-':
     print(output_str,)
   else:
-    output_file = io.open(output_file_path, 'w')
+    output_file = io.open(output_file_path, 'w', newline='\n')
     output_file.write(u'// This file was GENERATED by command:\n')
     output_file.write(u'//     %s %s\n' %
                       (os.path.basename(__file__), os.path.basename(file_path)))