Class proceedings are often high-profile cases, with important legal, social, and practical consequences. In this way, they resemble other kinds of test-case or public interest litigation, like constitutional challenges. Unlike those types of cases, however, class proceedings attract intervenors with less frequency and with more uncertain results. This article reviews the existing jurisprudence on interventions by and in class proceedings, identifies recurring themes and outcomes, and highlights the key judicial reasoning. The article closes by outlining a principled approach to addressing interventions in class proceedings and by class representatives.