Between 2000 and 2013, higher education (HE) in Colombia expanded substantially in response to greater demand, greater supply of capacity and programs on the part of HE institutions, and policies enhancing HE access and attractiveness. We use rich student- and program-level data to decompose the observed enrollment expansion, and we show that changes in HE supply, policy, and returns account for most of the expansion and have been critical to the inflow of low-ability students. We investigate the supply expansion and the opening of new programs and find that these were driven by the economic incentives facing the institutions.