A straightforward way to prevent students from leaving education without a higher secondary diploma is increasing the compulsory education age. The idea is that, by staying longer in school, more students eventually obtain a higher secondary diploma. This paper examines the impact of a one-year increase in compulsory school-age on dropping out of secondary education by a difference-in-differences analysis. For this, we exploit a recent compulsory education policy reform in the Netherlands. After controlling for confounding factors and observable covariates, we find that the one year increase in compulsory school-age reduces dropout by 2.5 percentage points. The effect, however, is entirely situated in the group non-liable to the policy reform. We observe that native Dutch vocational students, mostly without retention in grade, but also without a higher secondary diploma at hand, more often left school in the immediate period before the policy reform. Given the economic revival at that time, this may reflect anticipation of labor market opportunities. (Contains 8 tables and 5 figures.)