We provide a comprehensive review of what research on U.S. students and institutions has revealed about women’s decisions to persist in the economics major, and we identify key avenues for future research. We first document gender differences in introductory economics course enrolments and persistence in the major. We then explore commonly cited reasons for this gender gap in economics, including issues within the profession (chilly climate), the major (role models, quantitative emphasis), and classroom environment (grade sensitivity, relevance). Throughout this review we identify gaps in the existing research, focusing on the lack of generalizability of existing findings. Lack of generalizability arises because of the use of convenience data, including single institution administrative retrospective data. Based on this background, we offer a research agenda that would greatly enhance our understanding of why female students attrite at higher rates at each step of the major.