Numerous studies show that women are less likely than men to express attitudes and opinions about politics. To explore the origins of this gender gap, we use data from a series of surveys of the general public and international relations scholars in the United States between 2014 and 2023. These data show that the gender gap in political expression exists, even among knowledge elites; female IR scholars say they don’t know the answer to survey questions at higher rates than their male colleagues. We also find that differences in political knowledge explain a significant part of the gap in political expression; the highly educated female scholars we surveyed were less likely than women in the general public to say they didn’t know the answer to survey questions. At the same time, factors other than knowledge, including confidence, also matter. Our public opinion survey shows that women select extreme answers, such as “strongly agree/disagree” rather than simply “agree/disagree,” at lower rates than men. Despite high levels of education among the female scholars we surveyed, they too are more hesitant than their male counterparts to select extreme answers. These findings have important implications for civic participation as well as for the recognition of women’s expertise within the academy and society more broadly.