diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 37557796..d65fbc54 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -1287,6 +1287,7 @@ Visual Basic:
   primary_extension: .vb
   extensions:
   - .bas
+  - .cls
   - .frx
   - .vb
   - .vba