South Asian gay, bisexual, and other men who have sex with men (GBMSM) in the United States are subsumed under the broad, heterogeneous category of Asian GBMSM in national surveillance systems. Disaggregated data on their rates of HIV and sexually transmitted infection (STI) testing are not publicly reported. This is problematic as the diversity of ancestries, cultures, and customs across subgroups of Asian GBMSM may contribute to differential HIV and STI testing experiences. To address this deficit in knowledge, 115 South Asian GBMSM recruited through social media advertising and peer referral were surveyed about their patterns of HIV and STI testing. In the past 6 months, almost two-thirds ( = 72, 62.61%) had two or more male sex partners, and more than a quarter ( = 33, 28.70%) had condomless anal sex with two or more male partners. In the past year, more than one in four ( = 32, 27.83%) had not been tested for HIV, and more than two in five ( = 47, 40.87%) had not been tested for STIs. The prevalence of past-year HIV and STI testing was lower among participants aged ≥35 years and those who had never used pre-exposure prophylaxis. Participants who were partnered were less likely to have been tested for HIV, and those who were born outside the United States were less likely to have been tested for STIs in the past year. Findings highlight gaps in domestic HIV- and STI-prevention efforts with respect to adequately engaging South Asian GBMSM and suggest that some segments of this subgroup may benefit from targeted outreach.