Leisure activities that occur outside of the school hours may facilitate positive youth development.The experiences of youth in three categories of activities (basketball and football, other sports, and nonsports) are examined in this study. Based on prior research, it is hypothesized that students participating in basketball and football will experience more negative outcomes (i.e., problem behaviors, fewer positive peer influences, and lower academic achievement). Furthermore, specific experiences in these leisure activities are explored as potential mediators of the effects of participation. Results indicate that basketball and football participation is related to more negative experiences and outcomes, but these differences reflect selection of more at-risk youths into these activities. Implications of the findings are discussed. (Contains 8 tables and 5 notes.)