In this paper I offer an interpretation of Kant’s theory of perceptual error based on his remarks in the Anthropology. Both hallucination and illusion, I argue, are for Kant species of experience and therefore require the standard co-operation of sensibility and understanding. I develop my account in a conceptualist framework according to which the two canonical classes of non-veridical experience involve error in the basic sense that how they represent the world as being is not how the world is. In hallucination this is due to the misapplication of categories and in illusion to the misapplication of empirical concepts. Yet there is also room in this framework for a distinction in terms of cognitive functionality between the level of experience, which is merely judgementally structured, and that of judgement proper, which involves the free action of a conscious agent. This distinction enables Kant to allow for the otherwise problematic phenomenon of self-aware non-veridicality.