While sociologists have long argued that higher education has a secularizing influence, recent research emphasizes the moderating role of social contexts in the relationship between social class and religion. I extend this line of research by examining sources of cross‐national variation in the association between higher education and religiosity using survey data from more than 46,000 respondents in 39 nations. Multilevel models of a religiosity scale show (1) in the aggregate, higher education has a moderate, negative effect on the religiosity scale, (2) this effect varies considerably across nations, and (3) the negative effect of higher education on religiosity is most robust in relatively religious nations. These results demonstrate the importance of national contexts in moderating the effect of education on religiosity. The results also support a cultural diffusion argument that suggests that the highly educated are innovators and early adopters of secular behaviors but that low levels of religiosity then diffuse to less‐educated segments of a population as secularity becomes more common.