diff --git a/lib/recurly/resource.rb b/lib/recurly/resource.rb
index b5856003e..c8a1ac620 100644
--- a/lib/recurly/resource.rb
+++ b/lib/recurly/resource.rb
@@ -15,7 +15,8 @@ def requires_client?
     end
 
     def ==(other_resource)
-      self.attributes == other_resource.attributes
+      other_resource.is_a?(Recurly::Resource) &&
+        attributes == other_resource.attributes
     end
 
     # Hide instance variables to keep from accidental logging