We investigate gender differences in individual credit claiming for teamwork. In a large-scale online experiment, participants work on an interactive task in teams of two and subsequently report their subjective contribution to the teamwork. In three between-subject treatments, we incentivize participants to either i) state their beliefs about their contribution truthfully, ii) to exaggerate their contribution, or iii) to exaggerate and thereby harm the other team member. Our setup allows us to distinguish between overconfidence and exaggeration with and without negative externalities, and to test whether there is a gender gap in credit claiming. We find that men and women both equally overestimate their contributions, but men exaggerate more than women: As soon as there is an incentive to exaggerate, men claim to have contributed more than women, even when exaggeration harms the team member. This gender gap in credit claiming is particularly pronounced among very large claims and for high-contributors. Strategic misrepresentations of contributions to teamwork can thus have sizeable equity consequences on the labor market.