This paper examines the effect of age of marriage on women's schooling outcomes for 36 countries from Sub-Saharan Africa and South West Asia. We employ an instrumental variable approach to account for the endogeneity of early marriage driven by socio-economic and cultural factors. Our results show that delaying early marriage by one year is associated with an increase of half a year of education in Sub-Saharan Africa and nearly one third of a year of education in South West Asia as well as a lower likelihood of dropping out from secondary school of 5.5% in South West Asia.