Drawing on data gathered in the 2009 Monitoring the Future study of American youth, and controlling for race and noncompetitive exercise frequency, this research examined the explanatory effects of competitive sports participation on alcohol consumption and marijuana use as well as the nonmedical use of prescription pain relievers among American high school seniors. Also including a self-esteem index in multivariate analysis of covariance equations, the study found that, among males, football players used all three substances at comparably high levels. In addition, females with comparably low levels of self-esteem smoked marijuana and used prescription drugs more frequently. Limitations of the study and recommendations for future research are offered.