<p>Digital technologies, including smartphones, social media, and internet access, have influenced adolescent health-risk behaviours. Yet, evidence relating multidimensional digital exposure with substance use in low-and middle-income countries remains limited. The study examined the association between digital exposure and current substance use among adolescents in India and assessed whether parental monitoring modifies this relationship. Baseline data were analysed from a multicentric school-based study conducted across six geographically diverse regions of India. A total of 6,168 adolescents aged 10–19&#xa0;years were selected using a multistage cluster sampling method. Current substance use within the past three months was assessed using the WHO-ASSIST tool. Digital exposure was measured using a composite index of social media use, exposure to substance-related content, late-night device use, and perceived peer pressure from digital platforms. Multivariable logistic regression models estimated adjusted odds ratios (AORs) with 95% confidence intervals (CI), including the interaction effect for parental monitoring. The prevalence of current substance use was 11.2% and increased progressively across digital exposure categories, from 6.7% in the low-exposure to 16.6% in the high-exposure group (p &lt; 0.001). Compared with low exposure, moderate and high digital exposure were associated with higher odds of substance use (moderate: AOR 1.63, 95% CI 1.19–2.23; high: AOR 2.20, 95% CI 1.55–3.11). Interaction analyses found that parental monitoring provided only modest and inconsistent protection. Under high digital exposure, increased odds of substance use persisted across monitoring levels. Higher digital exposure was strongly linked with adolescent substance use in a dose–response pattern. Parental monitoring showed limited moderation of the observed association between digital exposure and substance use. Longitudinal research is needed to clarify temporal relationships and inform prevention strategies.</p>