In job applications, job interviews, performance reviews, and a wide range of other environ-ments, individuals are explicitly asked or implicitly invited to assess their own performance. In a series of experiments, we find that women rate their performance less favorably than equally performing men. This gender gap in self-promotion is notably persistent. It stays just as strong when we eliminate gender differences in confidence about performance and when we eliminate strategic incentives to engage in self-promotion. Because of the prevalence of self-promotion opportunities, this self-promotion gap may contribute to the persistent gender gap in education and labor market outcomes.