On the basis of self-determination theory it is proposed that adolescents' motives for forming and maintaining identity-relevant commitments can be either autonomous or controlled in nature. This study examined whether motives for identity commitments would add to the prediction of late adolescents' adjustment beyond the effect of strength of commitment per se. In addition, it was examined how late adolescents' identity-processing styles would relate to motives for commitment and whether motives for commitment would mediate between identity styles and adjustment. In a sample of 431 late adolescents it was found that autonomous and controlled motives were, respectively, positively and negatively related to adjustment even after taking into account the role of strength of commitment. Each of the three identity styles showed a specific pattern of associations with the motives for commitment, with an information-oriented style relating to the most autonomous and internalized motivational profile. Mediation analyses showed that at least part of the associations between identity styles and adjustment are mediated by motives for commitment. Directions for future research are discussed. (Contains 2 tables and 1 figure.)