diff --git a/Library/Homebrew/rubocops/components_order.rb b/Library/Homebrew/rubocops/components_order.rb
index 3f955d225b..0156072f9b 100644
--- a/Library/Homebrew/rubocops/components_order.rb
+++ b/Library/Homebrew/rubocops/components_order.rb
@@ -110,7 +110,7 @@ module RuboCop
         end
 
         def check_on_os_block_content(component_precedence_list, on_os_block)
-          on_os_allowed_methods = %w[depends_on patch resource deprecate! disable! conflicts_with]
+          on_os_allowed_methods = %w[depends_on patch resource deprecate! disable! conflicts_with keg_only]
           _, offensive_node = check_order(component_precedence_list, on_os_block.body)
           component_problem(*offensive_node) if offensive_node
           child_nodes = on_os_block.body.begin_type? ? on_os_block.body.child_nodes : [on_os_block.body]