This chapter explores the history of the “agrarian question,” or what to do about a deeply inequitable landowning system, in Brazil. It focuses on ideas and how they have interacted with actors, institutions and policy outcomes. It distinguishes between four periods. During the 1910s, pro-land reform ideas emerged but a conservative political context limited their influence. From the 1920s to the mid-1950s, such ideas diffused more widely, but there was little grassroots mobilisation for, or implementation of, reform. Between the late 1950s and the mid-1980s, conflict over land escalated and innovations arose in the ideational and institutional realms. Again, however, little land reform resulted. Finally, since the late 1980s, there have been major increases in mobilisation and reform. Nevertheless, the agrarian structure remains highly unequal.