diff --git a/lib/active_model/serializer/adapter/cached_serializer.rb b/lib/active_model/serializer/adapter/cached_serializer.rb
index 35b10168..076c057e 100644
--- a/lib/active_model/serializer/adapter/cached_serializer.rb
+++ b/lib/active_model/serializer/adapter/cached_serializer.rb
@@ -24,7 +24,7 @@ module ActiveModel
         end
 
         def fragment_cached?
-          @klass._cache_only && !@klass._cache_except || !@klass._cache_only && @klass._cache_except
+          @klass._cache && (@klass._cache_only && !@klass._cache_except || !@klass._cache_only && @klass._cache_except)
         end
 
         def cache_key