As work organizations become increasingly gender diverse, existing theoretical models have failed to explain why such diversity can have a negative impact on idea generation. Using evidence from two group experiments, this paper tests theory on the effects of imposing a political correctness (PC) norm, one that sets clear expectations for how men and women should interact, on reducing interaction uncertainty and boosting creativity in mixed-sex groups. Our research shows that men and women both experience uncertainty when asked to generate ideas as members of a mixed-sex work group: men because they may fear offending the women in the group and women because they may fear having their ideas devalued or rejected. Most group creativity research begins with the assumption that creativity is unleashed by removing normative constraints, but our results show that the PC norm promotes rather than suppresses the free expression of ideas by reducing the uncertainty experienced by both sexes in mixed-sex work groups and signaling that the group is predictable enough to risk sharing more—and more-novel—ideas. Our results demonstrate that the PC norm, which is often maligned as a threat to free speech, may play an important role in promoting gender parity at work by allowing demographically heterogeneous work groups to more freely exchange creative ideas.