PurposeTo perform a cross-cultural adaptation and validation of the Brazilian-Portuguese versions of the Brace Questionnaire in adolescent idiopathic scoliosis.MethodsA forward-backward translation process was employed to produce a Brazilian Portuguese version of the Brace Questionnaire, followed by comprehensive cross-cultural adaptation stages. The measurements of internal consistency and test–retest reliability were assessed by Cronbach’s a and intraclass correlation coefficient (ICC), respectively. The Pearson’s correlation coefficient was used to analyze the concurrent validity by comparison with the Scoliosis Research Society-22r questionnaire.ResultsA total of 84 scoliosis patients (age 13.4 ± 2.0 years, thoracic Cobb angle 33.3° ± 13.8°, and lumbar Cobb angle 29.8° ± 14.3°) were included. The Brace Questionnaire showed excellent internal consistency (Cronbach α = 0.93) and moderate reliability (ICC = 0.86). The correlations between the Brace Questionnaire and Scoliosis Research Society-22 were r = 0.66; p = 0.011. In addition, it was found that the Brazilian version of the Brace Questionnaire does not have ceiling and floor effects.ConclusionsThe Brazilian-Portuguese adaptation of the brace questionnaire shows excellent reliability and can be a valid tool for psychometric assessment in adolescent idiopathic scoliosis.