When filtering Django querysets across relationships, you can easily end up with duplicate objects in your results. This is a common gotcha that happens with both one-to-many (1:N) and many-to-many (N:N) relationships. Let’s explore why this happens and the best way to avoid it. The Problem When you filter a queryset by traversing a relationship, Django performs a SQL JOIN. If a parent object has multiple related objects that match your filter, the parent object appears multiple times in the result set.