While community-based groups are able to provide vital support to people living with HIV/AIDS (PLHIV), their organizational and technical capacities are limited, and they frequently operate in isolation from PLHIV groups. We evaluated a three-year project implemented by the International HIV/AIDS Alliance in Uganda to increase the involvement of PLHIV in the HIV/AIDS response and to improve access to and utilization of prevention, treatment, care, and support services for households affected by HIV/AIDS. Information sources included project monitoring data, interviews with 113 key informants, and 17 focus group discussions in 11 districts. The evaluation found that PLHIV groups reached large numbers of people with education and awareness activities and made a growing number of referrals to health facilities and community-based services. The project trained individuals living openly with HIV as service providers in the community and at designated health facilities. Their presence helped to reduce the stigma that previously deterred PLHIV from seeking care and encouraged individuals to disclose their HIV status to spouses and family members. The project has put into practice the widely endorsed principles of greater and meaningful involvement of PLHIV in a systematic manner and on a large scale. A wide audience - ranging from grassroots PLHIV networks and AIDS service organizations to national-level non-governmental organizations, government agencies, and international organizations - can benefit from the lessons learned.