Philosophical asceticism played an important role in the opposition to social injustice, oppression, and slavery across religious traditions in imperial and late antiquity in the Mediterranean world. A connection emerges from recent research between asceticism (or at least a strand thereof), the rejection of slavery as an institution, and the embrace of social justice in ancient philosophy, Jewish Hellenism, and especially Christianity in antiquity and late antiquity. When Christian ascetics chose poverty and low status in service to Christ, they were often also concerned for those who were victims of social injustice and oppression. Since at least some Christian – and Jewish, and ‘pagan’ – philosophical ascetics spoke explicitly of ‘justice’ in this connection, we can surmise that at least a part of them embraced asceticism also for the sake of justice.