We developed and evaluated a military-focused HIV prevention intervention to enhance HIV risk-reduction knowledge, motivation, and behaviors among Angolan soldiers. Twelve bases were randomly assigned to HIV prevention or control conditions, yielding 568 participants. HIV prevention participants received training in preventing HIV (4.5 days) and malaria (0.5 days). Control participants received the reverse. Monthly booster sessions were available after each intervention. We assessed participants at baseline, 3 and 6 months after the training. HIV prevention participants reported greater condom use and less unprotected anal sex at 3 months, as well as greater HIV-related knowledge and perceived vulnerability at 3 and 6 months. Within-group analyses showed HIV prevention participants increased condom use, reduced unprotected vaginal sex, and reduced numbers of partners at both follow-ups, while control participants improved on some outcomes at 3 months only. A military-focused HIV prevention intervention may increase HIV-related knowledge, motivation, and risk reduction among African soldiers.