It has been observed that, unlike other kinds of singular judgments, mental self-ascriptions are immune to error through misidentification: they may go wrong, but not as a result of mistaking someone else’s mental states for one’s own. Although recent years have witnessed increasing interest in this phenomenon, three basic questions about it remain without a satisfactory answer: what is exactly an error through misidentification? What does immunity to such errors consist in? And what does it take to explain the fact that mental self-ascriptions exhibit this sort of immunity? The aim of this paper is to bring these questions into focus, propose some tentative answers and use them to show that one prominent attempt to explain the immunity to error through misidentification of mental self-ascriptions is unsuccessful.