This was a statewide study of 3,189 11th grade students in the Midwest. The study used the American Drug and Alcohol Survey, which measured drug involvement based on recency and frequency of using 17 types of substances. The study included three measures of peer encouragement to use alcohol, marijuana, and other drugs. There were two sets of questions on the extent of participation in school and nonschool-based activities. The study found that school-based and nonschool-based extracurricular activities were statistically significant as related to drug involvement, past-year consumption of alcohol and marijuana, and getting drunk in the past year, even after controlling for peer influence; however, the effect of extracurricular activities was secondary in importance when compared to the influence of peers for explaining variance in substance use. The study advises that youth program providers should view extracurricular activities as a positive context for the reduction of substance use, in spite of the strong, direct influence of peers. 1 figure, 5 tables, and 27 references