The contours and correlates of sex segregation in higher education are explored using data from twelve advanced industrialized countries. Tertiary sex segregation is examined across two dimensions: field of study (horizontal segregation) and tertiary level (vertical segregation). The authors argue that the different aspects of female status in higher education (e.g., overall enrollments, representation at the post-graduate level, and representation in traditionally male-dominated fields of study) do not covary because each variable is affected in distinct ways by structural and cultural features commonly associated with "modernity." In particular, (1) ideals of universalism do more to undermine vertical segregation than horizontal segregation, and (2) some modern structural features may actually exacerbate specific forms of sex segregation. Consistent with these arguments, results suggest strongly integrative effects of gender-egalitarian cultural attitudes on distributions across tertiary levels, and weaker, less uniform cultural effects on distributions across fields of study (one notable exception being a strong positive effect on women's representation in engineering programs). Two modern structural features-diversified tertiary systems and high rates of female employment-show segregative effects in some fields and institutional sectors. Overall, few across-the-board integrative or segregative effects can be discerned that would lend support to evolutionary conceptualizations of gender stratification. Modern cultural and structural pressures are manifested unevenly and in contextually contingent ways.