diff --git a/.gitignore b/.gitignore
index c0117a795b..28ee9cf2a8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,3 +16,4 @@ railties/doc/guides/html/images
 railties/doc/guides/html/stylesheets
 *.rbc
 *.swp
+*.swo