Vietnam has a concentrated HIV epidemic, with the highest HIV prevalence being observed among people who inject drugs (PWID). Based on its experience scaling-up robust HIV interventions, Vietnam aims to further strengthen its response by harnessing the preventive benefits of antiretroviral therapy (ART). Mathematical modelling suggests that prioritizing key populations for earlier access to ART, combined with other prevention interventions, may have significant impact on the epidemic, cost-effectively reducing new HIV infections and deaths. Pilot studies are being conducted to assess feasibility and acceptability of expansion of HIV testing and counselling (HTC) and early ART among key populations and to demonstrate innovative service delivery models to address challenges in uptake of services across the care cascade. Earlier access of key populations to combination prevention interventions, combined with sustained political commitment and supportive environment for key populations, are essential for maximum impact of ART on the HIV epidemic in Vietnam.