An emerging HIV epidemic can be seen among men who have sex with men (MSM) in Vietnam. There are currently no evidence-based behavioral sexual risk reduction interventions for MSM in this setting. Between October 2012 and June 2013, 100 high-risk MSM from Ho Chi Minh City were enrolled in an open pilot trial to assess feasibility and acceptability of a group-based, manualized sexual risk reduction intervention, and to preliminarily examine changes in primary and secondary outcomes. Participants completed a behavioral assessment battery and HIV testing at baseline, 3, and 6 months post-baseline. Over 80.0 % of the sample was <25 years old and 77.0 % identified as Bong kin ("hidden," masculine-appearing). Feasibility and acceptability of the program was evidenced by 87.0 % retention for the intervention sessions, 78.0 % completion of the 6 month assessment, and positive responses on evaluation forms and qualitative exit interviews. There was a decline in the number of condomless anal sex acts from baseline (6.32) to 3 month (2.06) and 6 month (2.49) follow-up (p < .0001). These data support the need for further testing of this group-based, behavioral HIV prevention intervention to reduce sexual risk behavior among MSM in Vietnam in a randomized controlled efficacy trial.