It is well known that far fewer men than women enroll in tertiary education in the United States and other Western nations. Developed nations vary in the degree to which men are underrepresented, but the Organization for Economic Co-operation and Development (OECD) average lies around 45% male students. We use data from the OECD Education at a Glance statistical reports, the Program for International Student Assessment (PISA), and the World Values Survey to explain the degree to which men are underrepresented. Using a multiple regression model, we show that the combination of both the national reading proficiency levels of 15-y-old boys and girls and the social attitudes toward girls attending university can predict the enrollment in tertiary education 5 y later. The model also shows that parity in some countries is a result of boys' poor reading proficiency and negative social attitudes toward girls' education, which suppresses college enrollment in both sexes, but for different reasons. True equity will at the very least require improvement in boys' reading competencies and the liberalization of attitudes regarding women's pursuit of higher education. At this time, there is little reason to expect that the enrollment gap will decrease, given the stagnating reading competencies in most countries.