Abstract
<jats:p>In this study, we initially examined the psychometric properties of the Mongolian version of the Experiences in Close Relationships–Revised Child version (ECR-RC) based on 434 secondary school students’ data. Of these, data from 427 participants were included in the validity analyses, and 374 participants completed a two-week retest. Reliability and construct validity were evaluated using internal consistency analysis, test–retest reliability, exploratory and confirmatory factor analyses, and indices of convergent and discriminant validity. The expected two-factor structure, comprising attachment anxiety and attachment avoidance, was generally supported. However, several items were removed during model refinement because of low factor loadings or problematic cross-loadings, resulting in a final 24-item model. 24-item model demonstrated acceptable fit for both the father form (RMSEA = 0.0475, SRMR = 0.0507, CFI = 0.932, TLI = 0.923) and the mother form (RMSEA = 0.0474, SRMR = 0.0499, CFI = 0.931, TLI = 0.921). Reliability was satisfactory across both parental contexts, with composite reliability values above 0.70 and two-week intra-class correlation coefficients for individual items ranging from 0.731 to 0.888. Discriminant validity was supported, whereas convergent validity received only partial support. Overall, the findings indicate that the Mongolian ECR-RC demonstrates good reliability and acceptable psychometric properties for assessing attachment-related anxiety and avoidance in children and adolescents; however, further validation using independent and more diverse samples is recommended.</jats:p>