We study workplace peer effects in fertility decisions using a game theory model of strategic interactions among coworkers that allows for multiple equilibria. Using register‐based data on fertile‐aged women working in medium‐sized establishments in Denmark, we uncover negative average peer effects. Allowing for heterogeneous effects by worker type, we find that positive effects dominate across worker types defined by age or education. Negative effects dominate within age groups and among low‐education types. Policy simulations show that these estimated effects make the distribution of where women work an important consideration, beyond simply if they work, in predicting population fertility.