The last forty years have witnessed a remarkable boom in higher education around the world. Importantly, the boom in higher education has been concentrated among women, such that today in most higher-income countries, and many lower-income countries, more women than men attend and complete tertiary education. We present a model that explains the increase in higher education, particularly among women, in terms of a market for college graduates in which the supply of college graduates is function of the distribution of the costs and benefits of higher education across individuals. Examining evidence on these costs and benefits, we find no clear evidence that benefits are greater for women than men. Instead, it appears that differences in the total costs of college for women and men - primarily due to differences in the distributions of non-cognitive skills for women and men - explain the overtaking of men by women in higher education.