A B S T R A C T Increasing participation in decision-making processes by service users is one of the objectives of decentralisation reforms in Tanzania. The argument is that decentralisation enhances participation by all sections of the community, and by women in particular, and results in decisions that better reflect local needs. This paper examines the impact of decentralisation reforms on service users’ participation for delivery of water and health services in rural Tanzania, using a gender perspective and principal-agent theory. The paper investigates how decentralisation has fostered spaces for participation and how men and women use these spaces, and identifies factors that constrain or encourage women’s participation. It shows that decentralisation reforms have created spaces for service users’ participation at the local level. Participation in these spaces,