We examined factors associated with HIV self-testing (HIVST) willingness among male ever-testers and never-testers who participated in a midpoint survey of a cluster randomized controlled HIV prevention trial in Dar es Salaam. Linear mixed binary logistic regression models were constructed to examine factors (demographic, HIV risk behavior, and sexual/social network) associated with willingness to self-test. Sixtyseven percent of 301 never-testers were willing to self-test for HIV compared to 72% 577 of ever-testers. Among never-testers, having discussed testing for HIV with a sexual partner was the only factor associated with HIVST willingness (2.36, 95% CI: 1.35-4.15). For evertesters, younger men were less willing to self-test than older men while men with higher education were more willing to self-test than less educated men. Having a moderate/great HIV risk perception decreased the odds of HIVST willingness relative to no risk perception (0.40, 95% CI 0.23-0.70) for ever-testers. Discussing HIV testing with a sexual partner and having been encouraged to test for HIV by a friend were associated with higher odds of being willing to self-test (2.22, 2.23; 95% CI 1.34-3.67, 1.14-4.39, respectively) among ever-testers. These findings suggest that HIVST willingness is highly acceptable among both male ever-testers and never-testers.