We use data from the Baccalaureate and Beyond Longitudinal Study and propensity score weighting methods to estimate the effect of a double major on bachelor's degree recipients’ earnings within four years after college graduation. We classify each of a student's two majors in a double major combination as either “higher- or lower-paying,” based on the rank order of the average earnings of each major among single major students. Our analyses yield three main findings. First, within one year after graduation, double major graduates earn significantly less relative to their single major peers with the same higher paying major; however, by four years after graduation, their earnings are similar to those with the single higher paying major and significantly higher relative to those with the single lower paying major. Second, we find that double major graduates are more likely to be employed, work longer hours, and pursue graduate education than their single major peers four years after graduation. Finally, transcript data suggest that double major graduates take fewer classes in the higher paying major, which may explain their initial earnings penalty relative to those with the higher paying single major.