Substance use among teenage girls in Jamaica is more common than many realize and it’s often linked to other risky behaviours like unsafe sex. This study surveyed over 800 girls aged 15–19 across four parishes to understand what drives this trend. It found that peer pressure and risky sexual behaviour are strong predictors of substance use, while regular church attendance and close parental supervision, especially from mothers, can help protect against it. Nearly half of the girls had used more than one substance, including alcohol, marijuana, and cigarettes. The findings highlight the urgent need for Jamaica-specific research and interventions that consider the social environments these girls live in. By using an ecological approach that looks at individual, family, and community factors, the study offers a roadmap for creating more effective support systems for young women.