Gender-based violence and violence against children are significant problems in South Africa. Community mobilisation and gender-transformative programming are promising approaches to address and reduce violence. A quantitative evaluation of One Man Can, a gender-transformative community mobilisation programme in South Africa, found mixed results in increasing gender-equitable behaviours and reducing violence. To better understand these findings, we analyse longitudinal qualitative data from community mobilisers, community members and community action teams, exploring individual and community-level factors that facilitate and hinder change. Interviews and focus groups were transcribed and analysed. Participants self-reported changes in their gender-equitable attitudes and use of violence as a result of participation in the programme, although some participants also reported opposition to shifting to a more gender-equitable culture. Facilitators to change included the internalisation of gender-transformative messaging and supportive social networks, which was buoyed by a shared vocabulary in their community generated by One Man Can. Because the programme targeted a critical mass of community members with gender-transformative programming, mobilisers and community action teams were held accountable by community members to model non-violent behaviour. Results reinforce the importance of addressing facilitators and barriers to change at both individual and community levels.