Background: Substance abuse among adolescents is a growing public health concern worldwide, with long-term physical, psychological, and social consequences. Early onset of addiction increases vulnerability to mental disorders, academic decline, and risky behavior.

Aim: To assess the prevalence, patterns, and determinants of substance abuse among adolescents and identify associated socio-demographic risk factors.

Methods: A cross-sectional study was conducted among 500 adolescents (13–19 years) from schools and colleges using a pre-tested questionnaire. Data on substance type, frequency, initiation age, peer pressure, family history, and psychological factors were recorded. Statistical analysis was done using Chi-square and logistic regression; p < 0.05 was considered significant.

Results: The prevalence of substance abuse was 28%. Tobacco (41%), alcohol (32%), and cannabis (14%) were the most commonly used substances. Mean age of initiation was 15.6 years. Peer pressure (62%), family history (38%), academic stress (44%), and poor parental supervision (32%) were significant predictors (p < 0.05). Regular users showed higher rates of depression (31%) and school absenteeism (26%). Males were more affected than females (ratio 3:1).

Conclusion: Substance abuse is prevalent among adolescents and strongly associated with peer influence, psychological stress, and family environment. Early awareness, school-based interventions, counseling, and parental involvement are crucial for prevention.