diff --git a/app/models/post.rb b/app/models/post.rb
index e97a034a7..6cf017458 100644
--- a/app/models/post.rb
+++ b/app/models/post.rb
@@ -801,7 +801,7 @@ class Post < ActiveRecord::Base
     end
 
     def post_is_not_its_own_parent
-      if id == parent_id
+      if parent_id.present? && id == parent_id
         errors[:base] << "Post cannot have itself as a parent"
         false
       end