Violence against women and girls is a complex and multifaceted issue that is engrained in social and cultural realities, while impacting both the mental health and social wellbeing of survivors. The issue becomes even more challenging in the context of urban informal communities in cities like Mumbai where settlements are characterised by overcrowding, insubstantial housing, insufficient water and sanitation, lack of tenure, and hazardous locations. Psychosocial approaches to prevent and respond to violence against women and girls target a range of factors—behavioural, cognitive, emotional, interpersonal, social and environmental—with the aim of improving the health and wellbeing of women and girls. SNEHA’s experience suggests that an interdisciplinary approach of interventions delivered by a range of professionals, including social workers and mental health practitioners, will help in formulating a more comprehensive and pragmatic theory of social change. This chapter explores the conceptualisation, evolution and evaluation of a theory-driven, community-led psychosocial approach to violence prevention that emphasizes locally relevant and scalable solutions.