Some of the most male-dominated science, technology, engineering and mathematics occupations and degree programmes are found in the world's most affluent societies. This article assesses whether gender gaps in "attitudes" follow similarly surprising patterns. Multivariate analysis of eighth-graders' affinity for mathematics and aspirations for mathematically related jobs in 53 countries shows that the attitudinal gender gap is indeed larger in affluent "postmaterialist" societies. Moreover, both girls and boys view mathematics more negatively in these societies. The authors suggest that cultural ideals of individual self-expression, highly prevalent under conditions of broad-based existential security, operate to reduce girls' and boys' interest in pursuits thought to be economically practical but personally non-expressive. Girls may be particularly susceptible to this negative effect, because taken-for-granted cultural beliefs about core female personality traits (and girls' gendered understandings of their own authentic inner selves) are often at odds with dominant representations of mathematical and technical work.