Afterschool programs can support Asian-American young people by providing academic support and culturally specific programming designed to help them bridge their native and adopted cultures. However, little is known about the effect of afterschool participation on academic and social outcomes for Asian-American students. This causal-comparative study helps to fill this gap by studying the differences in achievement, behavior, and self-esteem between Hmong students who did and did not participate in afterschool programs in two high schools in the Central Valley of California. The focus on a specific ethnic group is a reminder that Asian Americans are not a single entity but a diverse set of groups. This study helps to fill another gap in the literature by focusing on the high school level, where the effects of afterschool programming are much less well documented than at the elementary and middle school levels. Among the findings were that study participants had a lower than average GPA compared to nonparticipants, had significantly better average attendance rates, and findings for self-esteem were mixed. Generally, The afterschool program produced positive outcomes for the Hmong high school students in the authors' sample. Implications for policy and practice are presented.