OBJECTIVES: There is insufficient evidence about the determinants of alcohol use amongst young people in India and other low-and middle-income countries, despite alcohol's high contribution to disease burden and increasing consumption in this population. We aimed to identify and estimate the determinants of alcohol use in a representative sample of 2716 young men from Bihar and Uttar Pradesh who participated in the 'Understanding the Lives of Adolescents and Young Adults' (UDAYA) study. METHODS: First, we developed an exploratory conceptual framework of potential alcohol use determinants in the study settings based on available literature. We then estimated the effects of 35 potential alcohol use determinants identified in the conceptual framework (including 14 latent factors identified through exploratory factor analysis) on any alcohol use in the past 3 years and regular alcohol use amongst past three-year drinkers, using mixed-effects logistic models. The determinants explored were operationalised using longitudinal data from the UDAYA study. RESULTS: Our adjusted models identified 18 determinants for past 3-year alcohol use and 12 determinants for regular use. Distal determinants (e.g., socioeconomic status), intermediate determinants (e.g., parental alcohol use, media use), and proximal determinants (e.g., emotional regulation, early tobacco use) were identified. Geographical variations in both outcomes indicate potential differences in unmeasured community-level determinants (e.g., alcohol availability and acceptability). CONCLUSIONS: Our findings extend the generalizability of several known determinants across settings, yet highlight the importance of addressing alcohol use in young people as a complex and context-dependent issue. Many identified determinants (e.g., education, media use, poor parental support, early tobacco use) are amenable to intervention through multi-sectoral prevention programs/policies. Such determinants should be the focus of ongoing policy/intervention development efforts in the region, and our revised conceptual framework may inform further research in India or similar South Asian settings.