Adolescent sexual and reproductive health (ASRH) is a major public health concern. A central predictor of ASRH is gender socialization; the process of learning and internalizing beliefs, attitudes and behaviors. This shapes adolescents’understanding of themselves and their relationships. Early adolescence (10 -14 years)(EA) is the time young people assume socially defined gender roles, resulting in pathways leading to particular SRH outcomes. While evidence indicates that gender norms influence SRH, it is not yet well understood how early adolescents acquire these norms and adopt behaviors. Understanding this process underpins efforts to empower girls and boys to determine their future SRH trajectories. The project, a partnership between UWC and UGent, aims to contribute to ASRH globally, and particularly in South Africa and Flanders. It links to a preceding Global Early Adolescent Study, led by Johns Hopkins University and the WHO, the first international study focussing on EA gender norms and SRH. In the first (finalized) qualitative phase we studied gender norms through in-depth interviews; in phase 2 (ongoing) we are developing scales to measure gender socialization and SRH. Phase 3 is a proposed quantitative study of adolescents (11- 14 years) with 3 measurements to explore associations between EA gender socialization and SRH outcomes. This proposal includes the first measurement of the study participants in Flanders and the first two in South Africa.