RESUMEN
Structural HIV prevention interventions have gained prominence as ways to address underlying social and cultural factors that fuel the HIV epidemic. Identifying theories that explain how structural interventions are expected to change such factors can substantially increase their success. The Tchova Tchova community dialogue program, a theory-based intervention implemented in 2009-2010 in the provinces of Zambezia and Sofala, Mozambique, aimed to change gender and sexual norms for HIV prevention. Through facilitated sessions, the program sparked critical thinking and open dialogue among participants. This article measures the program's effectiveness based on a sample of 462 participants and 453 nonparticipants. The results show that the program was successful in producing changes in three of the underlying structural factors of HIV: gender attitudes, gender roles, and HIV stigma. The program was also successful in changing other factors associated with HIV infection, including HIV prevention knowledge, discussion of HIV between sex partners, and having multiple sex partners.