Using a reform that increased parental leave generosity, we estimate workplace peer effects in leave-taking, focusing on fathers. Coworker fathers are more likely to take leave when exposed to more peer fathers affected by the reform. Effects are stronger in establishments with higher social capital and pre-reform leave use. We explain our findings showing that incumbent coworkers drive the effects, same-gender peer influences exceed cross-gender ones, the strongest peer effects run from higher- to lower-ranked occupations, and career penalties are absent for peer fathers. Peer effects extend to coworker fathers' partners, less so to coworker mothers' partners.