The Istanbul Convention is an important Council of Europe treaty aimed at preventing violence against women. Article 42 of the Istanbul Convention prohibits the use of ‘culture, custom, religion, or tradition’ in trials of defendants accused of violence against women. This article examines Article 42 from a transnational legal feminist perspective. As a treaty that applies to a wide range of countries, it should appreciate the significantly varying societal contexts across countries within the Council of Europe. It is argued here that the language of Article 42 does not go far enough to recognise this transnational diversity.