diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 1c346bdd..c60b63dd 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -224,6 +224,7 @@ CoffeeScript:
   primary_extension: .coffee
   extensions:
   - ._coffee
+  - .cson
   filenames:
   - Cakefile