This study sought to validate the Portuguese translation of a questionnaire on maltreatment of children and adolescents, developed by Russell et al. and to test its psychometric properties for use in Brazil. The original questionnaire was translated into Portuguese using a standardized forward-backward linguistic translation method. Both face and content validity were tested in a small pilot study (n = 8). In the main study, a convenience sample of 80 graduate dentistry students with different specialties, from Curitiba, PR, Brazil, were invited to complete the final Brazilian version of the questionnaire. Discriminant validity was assessed by comparing the results obtained from the questionnaire for different specialties (pediatric dentistry, for example). The respondents completed the questionnaire again after 4 weeks to evaluate test-retest reliability. The comparison of test versus retest questionnaire answers showed good agreement (kappa > 0.53, intraclass correlation > 0.84) for most questions. In regard to discriminant validity, a statistically significant difference was observed only in the experience and interest domains, in which pediatric dentists showed more experience with and interest in child abuse compared with dentists of other specialties (Mann-Whitney test, p < 0.05). The Brazilian version of the questionnaire was valid and reliable for assessing knowledge regarding child abuse by Portuguese-speaking dentists.