I estimate the effect of extracurricular participation on the high school dropout decision with a particular focus on at-risk students. Using a sample of tenth grade students from the National Education Longitudinal Study of 1988, I jointly estimate the dropout and participation decisions (including extracurricular offerings per student), and eligibility requirements as instruments for extracurricular participation. I include an interaction between the participation and at-risk indicators in the dropout equation because past disadvantages may differentially affect at-risk students. I also estimate alternative specifications to identify the effect of participation in different types of activities. Local average treatment effect estimates range from 14 to 20 percentage points, indicating that participants are significantly less likely to drop out of high school than they would have been if unable to participate, with similar estimates for both at-risk and not-at-risk students. These findings are relevant to policy makers and administrators seeking to increase high school graduation rates and improve educational outcomes.