This research aimed at identifying patterns of substance abuse among South African adolescents and exploring the relationship between psychological well-being and substance abuse. Psychological well-being was assessed with selected items of the Bar-On EQ-I and Diener's Life Satisfaction scale. Self-reported substance abuse patterns of 1 918 learners between the ages of 12 and 19 from 13 schools in Tshwane were recorded. Schools were selected to represent the population composition of the area. It was found that substance abuse (current alcohol use, excessive alcohol use, and use of illicit drugs) increased with age and that nearly twice as many males as females abused substances. Language group was found to be a determining factor with regard to current and excessive use of alcohol; however, it was not found to influence drug use. An analysis of variance showed that adolescents who used drugs had significantly lower levels of psychological well-being and life satisfaction. The same was not found for excessive use of alcohol. The results can contribute to a better understanding of substance use behaviour and to identifying adolescents who may be at risk of abuse.