This study analyzes the psychometric properties of the Spanish adaptation of the Relational Abilities Index (RAI) among university students in Mexico. The study employed a version of the RAI consisting of 128 items distributed across eight types of relational responses. The study evaluates its concurrent validity by calculating the relationship between relational abilities and intelligence, measured through the Wechsler Adult Intelligence Scale IV (WAIS-IV) and the G Factor test. The sample consisted of 40 university students, selected through non-probabilistic sampling. Results indicated moderate correlations between RAI scores and WAIS-IV subscale scores, particularly with visuospatial and abstract reasoning skills. Analyses of internal consistency of the RAI yielded a high Cronbach’s alpha coefficient, although split-half reliability was low, suggesting a need to review item homogeneity. This study provides preliminary evidence on the validity and reliability of the RAI in a Mexican context, pointing out the importance of adjusting item difficulty and discrimination to enhance psychometric accuracy. Implications for the assessment and training of relational skills in educational and clinical settings are discussed