In this paper I defend the claim that concepts are not public. I argue that two of the main constraints for theories of concepts, namely (1) that concepts are public and (2) that they serve to explain Frege Cases, are in tension. (1) requires concepts to be individuated coarsely, while (2) requires concepts to be individuated finely. Thus, no theory of concepts can accommodate both (1) and (2). I argue that (2) is a non-negotiable constraint for theories of concepts, while (1) is negotiable. Therefore, theories of concepts should individuate concepts finely enough to solve Frege Cases, and claim that concepts are not public.