With reference to its unique characteristics, the European Union (EU) regularly requests a special position in treaty cooperation or external judicial control mechanisms. Recurrently, these requests are successful and lead to the EU being treated differently from other treaty parties. These situations have been captured by the concept of ‘European exceptionalism’. EU requests for special treatment can also be witnessed in the supportive and facilitative procedures of compliance mechanisms in international environmental law. In those mechanisms, however, EU requests for special treatment are subject to careful scrutiny, and are even met with strong opposition by treaty institutions and treaty partners. Taking a closer look at the EU’s participation in compliance mechanisms, the present article discusses how certain unique EU characteristics may prompt an EU request for special treatment under compliance mechanisms and explores how compliance institutions and treaty partners have treated existing requests so far. With this outside perspective of non-EU actors, it is possible to understand where such requests can be successful and where they fail to be. In this way, the insights gained permit reflection upon the EU’s participation in compliance mechanisms and whether it truly constitutes a further phenomenon of ‘European exceptionalism’.