INTRODUCTION: HIV prevalence among men who have sex with men (MSM) in Vietnam is increasing, while annual HIV testing uptake has remained consistently low, posing a significant challenge to reaching the 90-90-90 goals. Barriers to MSM seeking HIV testing include concerns regarding confidentiality and lack of convenient testing options. Two new HIV testing strategies-HIV lay provider and HIV self-testing (HIVST)-were piloted alongside intensive social media outreach to increase access to and uptake of HIV testing among MSM not actively engaged in services. METHODS: We measured the proportion of first-time MSM HIV testers opting for HIV lay or self-testing, and factors that were associated with first-time testing, as part of a larger HIV lay and self-testing study among key populations in Vietnam. We also assessed MSM satisfaction with HIV lay or self-testing, and testing location and provider preferences. Finally, we calculated linkage to care cascade among MSM that were diagnosed and enrolled in anti-retroviral therapy (ART) services. RESULTS: Among MSM that sought HIV lay and self-testing, 57.9% (n = 320) and 51.3% (n = 412) were first-time testers respectively. In the final adjusted models, the odds of being a first-time tester and opting for HIV lay testing were higher among MSM who were young, had lower levels of income and had never exchanged sex for money; for HIVST, the odds of being a first-time HIV tester were higher among MSM that had attained lower levels of education. HIV lay and self-testing resulted in higher detection of new HIV cases (6.8%) compared to conventional HIV testing among key populations (estimated at 1.6% in 2016), while MSM linked to testing through social media interventions presented with even higher HIV-positivity (11%). Combined, 1655 HIV cases were diagnosed and more than 90% were registered for ART services. CONCLUSIONS: Our findings suggest that MSM-delivered HIV testing and self-testing, promoted through online or face-to-face interactions, offer important additions to MSM HIV testing services in Vietnam, and could significantly contribute to epidemic control by increasing HIV testing among harder-to-reach and higher-risk MSM, effectively enrolling them in ART, and reducing onward transmission.