Background: Macao has become a major transit center in the international drug trade because of its special geographical position. With its unique environment, adolescent drug abuse has become an increasingly serious problem. Reversing this trend requires a good understanding of the risk factors for addictive behavior. Objectives: Based on the differential association theory, this study aims to identify whether association with drug-using peers and friends and interaction of age and peer influence are risk factors for adolescents’ drugs use. Methods: We use data from a probability sample of more than 8,000 students enrolled in elemental and secondary schools in Macao in 2014 with a revised questionnaire from Monitoring the Future. Linear regression analysis was employed to test the relationships between these risk factors and adolescents’ drugs use. Results: Analyses revealed that students who had more drug-using peers perceived more harm of drug use. Furthermore, as age increases, the effect of drug-using peers on adolescents’ drug abuse becomes stronger. In other words, the interaction has the strongest effect on the dependent variable when young adults are at university, while it has the weakest effect when they are in elementary school.