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A sample of 9th-grade students (1,293 individuals, 51% girls) attending compulsory schools in Reykjavik, Iceland, was surveyed and followed up 3 years later. The relationship between perceived control and substance use is examined concurrently at age 14 for experimentation with tobacco and alcohol and longitudinally (14–17 years of age) for daily smoking, heavy drinking, and illicit drug use. Taking into account sociodemographic characteristics (family structure, socioeconomic status, and gender) and parental and peer use, the results of concurrent analyses indicate that adolescents who expressed more personal control were less likely to have smoked and to have had a drink at age 14. Longitudinal analyses showed that perceived control at age 14 predicted both daily smoking and illicit drug use among girls at age 17 but not among boys. Conversely, perceived control did not predict heavy drinking among adolescents.