This study examined the relative contribution of psychological engagement with a service activity and number of hours spent in that activity as predictors of change over time in community belonging and social responsibility. Sixty-eight primarily rural adolescents participated as teen leaders in a sexuality education program, and completed assessments of social responsibility and community belonging before and after program participation. Psychological engagement with the service activity and number of hours spent were used to predict changes in social responsibility and community belonging, while controlling for gender, prior program participation, and sexual behaviour history. Psychological engagement, but not number of hours spent, accounted for significant unique variability of change in community belonging and social responsibility.