Capitalizing on emerging data suggesting that HIV preventive behaviors can be positively affected by Internet-based programs, we developed and tested CyberSenga, an Internet-based, comprehensive sexuality education program for adolescents in Mbarara, Uganda. Three hundred and sixty-six secondary school students were randomly assigned to either the 5-lesson program (+ booster) or a treatment-as-usual control. At three-month follow-up, intervention participants provided feedback on program acceptability. Six focus groups with intervention participants were additionally conducted after the final follow-up at 6 months. Data support a hypothesis of feasibility: Despite schedule interruptions, 95% of intervention participants completed all 5 modules; only 17% deviated from the once-a-week intended delivery schedule. Internet service was uninterrupted during the field period and, in general, the technology performed to specifications. The intervention also appears to be acceptable: 94% of intervention youth somewhat or strongly agreed that they learned a lot and 93% said they were somewhat or very likely to recommend the program. Although more than two in three youth somewhat or strongly agreed that the program talked too much about sex (70%) and condoms (75%), 89% somewhat or strongly disagreed that “I do not think kids like me should do the CyberSenga program”. Feedback from focus group participants further suggested that the content was generally acceptable and did not contradict local norms in most cases. In fact, despite concerns from some local stakeholders to the contrary, information about condoms did not appear to be confusing or contradictory for youth who were abstinent. Nonetheless, some of the sexual topics seemed to be unfamiliar or uncomfortable for some participants – particularly brief references to oral and anal sex. Together, both qualitative and quantitative data suggest that the program is a feasible and acceptable way of delivering HIV preventive information to both sexually experienced and inexperienced adolescents in Mbarara, Uganda.