Developing a capacity for exercising agency is an important developmental task of adolescence. Many organized youth programs provide adolescents opportunities to build their capacity to exercise agency. The researchers tested hypotheses that adult youth program leader's directive assistance and autonomy support would promote adolescents’ capacity for agency. They surveyed 441 high school adolescents and 11 adult advisors from 10 Future Farmers of America chapters twice over 2 years. Adolescents self‐reported on their capacity for agency and advisors reported on each adolescent's capacity. Directive assistance and autonomy support correlated with the capacity for agency within both time points. Only autonomy support predicted adolescents’ capacity for agency over time. Implications of leader's support for adolescents’ capacity for exercising agency are discussed.