Over the years, many suggestions have been made on how to reduce the importance of family background in political recruitment. In this study, we examine the effectiveness of one such proposal: the expansion of mass education. We utilize a difference-in-difference strategy to analyze how a large school reform launched in Sweden in the 1950s, which lengthened schooling and postponed tracking, affected the likelihood of individuals with different family backgrounds to run for public office. The data come from public registers and pertain to the entire Swedish population born between 1943 and 1955. The empirical analysis provides strong support for the view that improved educational opportunities for individuals from disadvantaged backgrounds can be an effective means to reduce the social bias of elected assemblies.