Comprehensive sexuality education (CSE) – including learning about relationships, gender and gender-based violence (GBV), sex, sexuality, and sexual and reproductive health and rights (SRHR) – can empower young people to make informed, autonomous decisions regarding their current and future relationships. CSE may also influence a positive shift in social norms which underpin violence against women and girls (VAWG), such as harmful notions of masculinity, and rigid gender roles and stereotypes – both in schools and the wider community. Drawing on global evidence on CSE interventions and primary and secondary research in Cambodia and Uganda1, this report explores the extent to which CSE may be a key mechanism to promote gender equality, shift harmful social norms and prevent VAWG. This report finds compelling evidence that CSE can be seen not only as part of a quality education, but also as part of a holistic approach to preventing VAWG. However, more evidence on ‘what works’ in changing attitudes on gender equality and reducing VAWG as part of CSE delivery is needed.