Objectives: The purpose of this study was to assess the validity and reliability of the Spanish version of PIDAQ for application in adolescents. Study Design: The questionnaire was translated, cross-culturally adapted and completed by 627 adolescents (366 12-year-olds and 261 15-year-olds). The adolescents were also examined by 4 examiners who had been calibrated against a gold standard and relative to each other (Kappa >0.85) in determining treatment need with the Dental Aesthetic Index (DAI) and the Index of Orthodontic Treatment Need (IOTN) DHC and AC components. Results: Cronbach´s alpha of the translated PIDAQ was 0.90. The 23 items of the questionnaire were divided into four domains that explained 60% of the variance. The test-retest reliability of the questionnaire was 0.93. Discriminant validity revealed a significant association between the scores for the questionnaire and its subscales or domains and those for the DAI, IOTN-DHC and IOTN-AC treatment need indices. Adolescents with orthodontic treatment need scored higher in the questionnaires. Conclusions: The results show that the Spanish version of PIDAQ has a very similar internal structure and psychometric properties to those of the original questionnaire and demonstrate its validity for use with Spanish adolescents.