The Marriage Transitions in Malawi Project (MTM) consists of a longitudinal dataset on young women and men in central Malawi, one of the poorest countries in the world, where marriage is nearly universal, and most women and men marry before the age of 20. The data are intended to support the study of the social and economic influences on the timing of key life events among young people, such as leaving school, engaging in sex for the first time, and marrying. These pivotal moments and experiences shape future life trajectories. The project also sought to identify whether and how socioeconomic conditions and gender might influence an individual’s chances of acquiring HIV. The rich MTM panel data can contribute to understanding the forces that drive young lives and inform policy interventions.