Constitutivist accounts of self-knowledge argue that a noncontingent, conceptual relation holds between our first-order mental states and our introspective awareness of them. I explicate a constitutivist account of our knowledge of our own beliefs and defend it against criticisms recently raised by Christopher Peacocke. According to Peacocke, constitutivism says that our second-order introspective beliefs are groundless. I show that Peacocke’s arguments apply to reliabilism not to constitutivism per se, and that by adopting a functionalist account of direct accessibility a constitutivist can avoid reliabilism. I then argue that the resulting view is preferable to Peacocke’s own account of self-knowledge.