Introduction: The Intolerance of Uncertainty Scale – Short Version (IUS-12) is a measure of trait intolerance of uncertainty. Objective: The purpose of the present study was to conduct a cross-cultural adaptation of the IUS-12 for use in Brazil and to investigate the scale’s psychometric properties. Methods: The research was conducted via an online research platform with a sample (n = 704; 80.1% female and 19.9% male) from different states in all five regions of Brazil. Participants were adults between 18 and 59 years of age (mean = 26.74; standard deviation = 8.36) who completed the Brazilian version of the IUS-12 online along with other anxiety-related measures. Results: Confirmatory factor analysis demonstrated that the original two-dimensional structure fit the sample well. The total score for the scale had good internal consistency (Cronbach’s alpha [α] = 0.88), as did both subscales (i.e. Prospective IU α = 0.79; Inhibitory IU α = 0.86). Conclusions: The results demonstrated strong positive correlations with measures of anxiety-related constructs, contributing to the transdiagnostic understanding of IU. The IUS-12 appears to be a useful tool for assessment of IU and its availability has several implications of theoretical importance and practical utility for understanding of psychopathology and uncertainty.