diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 3382a741..f2b956a8 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -792,6 +792,7 @@ Ruby:
   - Rakefile
   - Thorfile
   - Gemfile
+  - Guardfile
   - Vagrantfile
 
 Rust: