Using nationally representative data on individual subjective views on gender roles, we examine the gender gap in educational achievement in Turkey and show that the cultural bias against the education of girls is a fundamental factor behind their low educational attainment in socially conservative societies. The 1997 education reform in Turkey extended compulsory schooling from 5 to 8 years. Using the reform as a natural experiment, we investigate the impact of the reform on the effects of mothers’ traditional views in determining children’s educational attainment. We find that the reform helped reduce school dropout rates across the country. Nevertheless, regardless of the mother’s view on gender roles, the reductions in school dropout rates were similar for boys and girls, failing to eliminate the gender gap against girls. Turkey is an excellent environment to study the effects of societal gender roles since it combines modernity with traditionalism and displays a wide spectrum of views on gender roles. It is also one of the few developing countries where a gender gap to the detriment of females still exists in educational achievement.