Effective altruism is a philosophy and a social movement that aims to revolutionise the way we do philanthropy. It encourages individuals to do as much good as possible, typically by contributing money to the best-performing aid and development organisations. Surprisingly, this approach has met with considerable resistance among activists and aid providers who argue that effective altruism is insensitive to justice insofar as it overlooks the value of equality, urgency and rights. They also hold that the movement suffers from methodological bias, reaching mistaken conclusions about how best to act for that reason. Finally, concerns have been raised about the ability of effective altruism to achieve systemic change. This article weighs the force of each objection in turn, and looks at responses to the challenge they pose.