Statement of problem: This study aimed to analyse the ability of a model based on achievement motivation and self-determination theories to predict adherence to competitive sport. This model incorporated commitment as predictor of adherence. A prospective study was performed with a sample of 302 handball players aged between 14 and 18 years. Structural equation modelling gave support to the model proposed. It was verified the sequence of relationships between perceptions of coach-created mastery climate, psychological needs, self-determined motivation, commitment, and adherence. The major contribution of the study was to confirm a motivational model of adherence based on social-cognitive theories, considering commitment as a predictor of adherence.