This article introduces a sport-specific theoretical model of commitment. Sport commitment is defined as a psychological state representing the desire or resolve to continue sport participation. The Sport Commitment Model proposes that sport commitment is determined by sport enjoyment, involvement alternatives, personal investments, social constraints, and involvement opportunities. Greater sport enjoyment, personal investments, social constraints, involvement opportunities, and less attractive involvement alternatives are predicted to lead to higher levels of sport commitment. Constitutive definitions were established for each of the model's components, and questionnaire items were developed. Results from the first empirical test of the model conducted with girls (n = 95) and boys (n = 83) participating in a Little League program showed that the questionnaire items formed reliable scales. Correlational analyses demonstrated that several predictors were related to sport commitment as hypothesized. Stepwis...