diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 854d2b9c..08271374 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -666,6 +666,7 @@ Ruby:
   - .gemspec
   - .irbrc
   - .thor
+  - .rbuild
   filenames:
   - Capfile
   - Rakefile