The notion of a distinction between merely formal freedom and real, substantive freedom is common in both philosophy and political rhetoric. However, Ian Carter contends that this distinction faces coherence and usefulness problems. Contra Carter, I argue that it is coherent, meaningful, and clarifies significant philosophical disagreements about the right to freedom. I define the formal-substantive freedom distinction by outlining a non-univocal conception of each term, then explain why the distinction so conceived is both philosophically and practically significant. I review Carter’s arguments, extract two potential objections to my account, and offer my replies.