diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index 13dd374f9c738..e88a8304b52cd 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -618,7 +618,7 @@ def ==(comparison_object)
     def hash
       id = self.id
 
-      if primary_key_values_present?
+      if self.class.composite_primary_key? ? primary_key_values_present? : id
         self.class.hash ^ id.hash
       else
         super