Greater participation of women in water management and decision-making is expected to improve outcomes for both women and the wider community. Global evidence indicates that women’s participation in Water User Committees (WUCs) has been limited; yet their involvement in management has correlated with more effective water systems. This analysis of water inventory data from Vanuatu considers how women’s participation in WUCs affects water management and system functionality. Women represent only 16 per cent of committee membership; however, their involvement in key WUC roles was associated with more effective water management, including regular meetings and revenue collection, and improved functioning of water systems. This evidence of women’s involvement is proving useful in advocacy efforts to improve the gender balance in WUCs, and targets for female membership are being considered for inclusion in water supply legislation.