We partially identify the average treatment effect of education on earnings and nonparametrically estimate its upper bound for African, Coloured (mixed race) and White males in South Africa. We address endogenous selection into education, cohort effects and endogenous selection into work. Using the September 2007 South African Labour Force Survey, the upper bound estimates are considerably lower than existing parametric point estimates of the return to education. As a lesson, policy makers should focus less on increasing the amount of education obtained by Africans and Coloureds, but rather on measures that can grow the return to existing levels of education.