Conspiracy theorists believe that powerful agents are conspiring to achieve their nefarious aims and also to orchestrate a cover-up. People who suffer from impostor syndrome believe that they are not talented enough for the professional positions they find themselves in, and that they risk being revealed as inadequate. These are quite different outlooks on reality, and there is no reason to think that they are mutually reinforcing. Nevertheless, there are intriguing parallels between the patterns of trust and distrust which underpin (...) both conspiracy theorising and impostor thinking. In both cases subjects distrust standard sources of information, instead regarding themselves as especially insightful into the underlying facts of the matter. In both cases, seemingly-anomalous data takes on special significance. And in both cases, the content of belief dictates the epistemic behaviour of the believer. This paper explores these parallels, to suggest new avenues of research into both conspiracy theorising and impostor syndrome, including questions about whether impostor syndrome inevitably involves a personal failure of rationality, and issues about how, if at all, it is possible to convince others to abandon either conspiracy theories or impostor attitudes. (shrink)