Objectives: The aim of this study is to translate into Portuguese-Brazilian language and adapt cross-culturally to the Brazilian population the Orthognathic Quality of Life Questionnaire (OQLQ). Study Design: The cross-cultural adaptation process followed six stages which are; (I) initial translation, (II) synthesis of the translation, (III) back translation, (IV) expert committee and (V) test of the prefinal version. For validation process, the OQLQ results were compared with Oral Health Impact Profile Questionnaire (OHIP-49), with the generic SF-36 Quality of Life Questionnaire and a visual analogue scale. A convenience sample of 25 patients was selected in two Southern Brazilian states of Santa Catarina and Rio Grande do Sul. Results: Internal consistency analysis of the OQLQ-Brazilian showed good correlation for items or domains and the test-retest reliability also presented excellent intra-class correlation coefficients. OQLQ-Brazilian exhibited a weak and negative correlation with SF-36, and good correlation with OHIP-49. Conclusion: The OQLQ-Brazilian preserved and reached equivalence with its original source and the findings also corroborate that there is good evidence for the construct validity. The demonstration of its reproducibility, reliability and validity makes this instrument an additional useful parameter for evaluation of the impact of dentofacial deformity over the quality of life for Brazilians. © Medicina Oral.