Background: Research on traditional gender beliefs has highlighted their psychological impact and social implications for women. The purpose of this study was two-fold: firstly, to explore the relationship between women’s traditional gender beliefs, intimate partner violence, stress and depression, and secondly, to adapt and validate the Spanish version of the Multicultural O’Kelly Women’s Beliefs Scale. Based on the Rational Emotive Behavior Therapy framework, traditional gender beliefs were expected to be associated with higher levels of intimate partner violence, stress and depression. We also expected to obtain a psychometrically-sound factor structure of the Multicultural O’Kelly Women’s Beliefs Scale.Methods: A sample of Spanish women (N=322) completed the Multicultural O’Kelly Women’s Beliefs Scale, the Beck’s Depression Inventory II, the Modified Conflict Tactics Scale, and the Stress Perceived Scale. To test the psychometric properties of the Multicultural O’Kelly women’s beliefs scale we implemented exploratory and confirmatory factor analyses and an analysis of the area under the curve.Results: Regarding the psychometric properties of the scale, statistical analysis revealed a one-factor dimensionality (Global traditionalism) and supported a reduction of items in the original instrument. The abbreviated version (eight items) obtained the best fit indices. Considering the association between traditional gender beliefs and psychological outcomes, we found that traditional gender beliefs were associated with increased severity of stress, depressive symptoms and reciprocal verbal aggression. Conclusion: The Spanish adaptation of the Multicultural O’Kelly women’s beliefs scale provided a very short, psychometrically robust and clinically relevant measure of traditional gender beliefs. In addition to the association between traditional gender beliefs and mental health outcomes, an important finding was the relationship between traditional gender beliefs and intimate partner violence. Our scale might be used in clinical settings by helping women to identify their traditional gender beliefs and replace them by healthy and goal–oriented beliefs, which would also contribute in achieving a more egalitarian society.