diff --git a/Library/.rubocop.yml b/Library/.rubocop.yml
index 5d4dcfa749..3636e41d3b 100644
--- a/Library/.rubocop.yml
+++ b/Library/.rubocop.yml
@@ -59,6 +59,7 @@ Homebrew/MoveToExtendOS:
   Exclude:
     - "Homebrew/{extend,test}/**/*"
     - "Taps/**/*"
+    - "Homebrew/os.rb"
 
 # enable all Homebrew custom cops
 Homebrew: