Psychological determinants of brace-wear compliance were analyzed among 113 patients who used a brace because of an adolescent idiopathic scoliosis (92%), kyphosis (5%), or both (3%). The results showed that noncompliant girls did not expect to succeed in dealing with scoliosis and that they were anxious about the possibility of failure. They also had low self-esteem and did not seek social support from other people. Noncompliant boys, in contrast, had high self-esteem and high achievement success expectation. Among patients with a short time of brace use, low compliance was best predicted by low amount of reflective thinking and a good body-image. In turn, among patients who had used the brace for >6 months, low compliance was best predicted by high amount of reflective thinking, poor body-image, low social success expectation, and low master orientation in social behavior. Only sleeping problems predicted compliance across gender and the time of brace use: the more the patients experienced sleeping problems, the less they used the brace.