GAGE is a programme conducting longitudinal research in several developing countries. This dataset is one of three GAGE workstreams in Ethiopia and follows the lives of more than 10,000 young people living in both urban and rural areas of Ethiopia, over nine years. Baseline comprised a sample of nearly 7,000 adolescents (Core Respondents) in two age cohorts (younger adolescents aged 10-12 years and older adolescents age 15-17 years at the time of baseline data collection), as well as their caregivers and communities. The research sample, composed of both randomly sampled and purposely selected adolescents and their families, was largely recruited in 2017-2018 from rural areas of three regions (Afar Zone 5, Amhara, and Oromia) and three cities (Batu, Debre Tabor, and Dire Dawa), with additional participants recruited at subsequent waves.