Sociosexuality describes the willingness to engage in sexual activities outside of committed relationships. Across two studies, we tested the factorial structure and reliability of the Revised Sociosexual Orientation Inventory (SOI-R) in Brazil. Study 1 explored the factor structure of the instrument within a sample of 178 individuals from the general population, supporting the proposed three-factorial structure of the SOI-R and showing good internal consistencies. Study 2 corroborated the three-factorial structure through a confirmatory factor analysis (ML) within a sample of 225 undergraduate students. Correlations between the SOI-R and other psychological variables (e.g. dark triad, mate value) replicated and extended previous studies from other countries. For example, among men, psychopathy and Machiavellianism correlated with the behavioural component of the SOI-R. Multi-group CFA indicated that the SOI-R is mainly invariant across gender. Thus, overall, our results demonstrate that the SOI-R is psychometrically suitable to evaluate sociosexuality in Brazil. The current studies show that the SOI-R is also reliable and valid in a non-Western country, providing further support for its theoretically driven three-factor structure across human cultures. •We validated the sociosexual orientation inventory (SOI-R) in Brazil.•The proposed three-factorial structure was found in two studies.•We demonstrated that the SOI-R is partially invariant across gender.•Theoretical meaningful correlations of sociosexuality with mate value and personality were found.