Violence against women and girls (VAWG) is preventable. Over the last two decades, VAWGprevention practitioners and researchers have been developing and testing interventions to stop violence from occurring, in addition to mitigating its consequences. The evidence base now shows that we can prevent VAWG through a range of interventions, within programmatic timeframes. Globally, there is also a growing consensus around ‘what works’ – the critical elements required for effective VAWG prevention. Key elements of effective design and implementation are summarised in Jewkes et al (2020) and in Box 1 (page iv). To advance the field of VAWG prevention, the UK Department for International Development (DFID) has invested in the What Works to Prevent Violence against Women and Girls programme (What Works), which evaluated 16 VAWG-prevention interventions in 14 subSaharan African, Asian and Middle Eastern contexts, over six years (2014–2019). At the start of the programme, What Works reviewed the global evidence on VAWG prevention published between 2000 and 2013 (Fulu, Kerr-Wilson and Lang, 2014). The rigorous, in-depth review of the state of the field presented in this report is an update of the 2014 review and has been undertaken at the end of What Works to summarise what is now known five years on about what works to prevent violence, and to capture the contribution that What Works has made to this wider evidence base. The growth in knowledge and evidence on VAWG prevention has inspired the RESPECT framework (WHO, 2019), which captures the violence prevention strategies known to be effective. In addition to the evidence-informed programming discussed in this review, RESPECT emphasises the importance of strengthening enabling conditions for prevention, including laws and policies supporting gender equality and women’s rights, an effective and accountable justice system, comprehensive services for survivors, and resourcing women’s rights organisations and movements.