In Ethiopia, 50% of the population is younger than 19 years. However, 88% of children and adolescents experience multi-dimensional challenges across nutrition, health and education. Rolled out in 2003, the Ethiopian Government's national Health Extension Programme (HEP) provides key health, sanitation and family planning services to disadvantaged groups. We aim to evaluate the effects of HEP on five dimensions of adolescent development, including teen marriage and teen pregnancy in girls. We will use four rounds of data from the Young Lives older cohort of 1,000 young people between 2000-13. The study exposure is self-reported receipt of HEP following programme rollout in 2003. Outcomes are measured when participants were 19 years.