This paper provides experimental evidence on the electoral effect of a large education reform in a developing democracy. The reform significantly improved school quality on many dimensions (Romero, Sandefur, & Sandholtz, 2020). In this paper, I show that the reform reduced the incumbent party's pres- idential vote share by 2.1 percentage points (5%). The reform also reduced teachers' job satisfaction, support for the incumbent government, and political engagement. Electoral effects were positively correlated with effects on teachers' political engagement; the reform lost most votes where it caused greatest political disengagement of teachers.