This paper presents an overview of gender differences in education outcomes in OECD countries. A rich set of indicators describes the improvement of educational attainment among women over the past decades, and various dimensions of male under-performance in education. Possible explanatory factors include incentives provided by changing employment opportunities for women, demographic trends, as well as the higher sensitivity of boys to disadvantaged socio-economic backgrounds. Gender differences in field of study and in performance by subject are found to be related to attitudes and self-perceptions towards academic subjects, which are in turn influenced by social norms. A number of policy options to address gender gaps are presented in the final section of the paper.