A bstract Aim: To cross-culturally adapt and validate the Vietnamese version of the Index of Dental Anxiety and Fear – Core Module (IDAF-4C) and assess its psychometric properties among adult dental patients in Vietnam. Materials and Methods: A cross-sectional study was conducted with 243 adult patients at a university dental hospital in Hanoi. The English IDAF-4C was translated into Vietnamese (V-IDAF-4C) following established cross-cultural adaptation guidelines. Reliability was assessed using Cronbach's α and exploratory factor analysis (EFA) with principal axis factoring and varimax rotation. Convergent validity was evaluated by correlating the V-IDAF-4C with the Vietnamese Modified Dental Anxiety scale (MDAS) using Spearman’s coefficient. Results: The V-IDAF-4C demonstrated excellent internal consistency (Cronbach’s α = 0.88). EFA confirmed a unidimensional structure, with a single factor explaining 54.78% of the total variance (eigenvalue = 4.38) and strong factor loadings for all eight items (ranging from 0.42 to 0.87). Strong convergent validity was established through a significant positive correlation with the MDAS (Spearman’s ρ = 0.73, 95% confidence interval: 0.67–0.79; P < 0.01). The prevalence of moderate-to-high dental anxiety was 28.39% (19.34% moderate, 9.05% high) according to the V-IDAF-4C scale. Conclusion: The Vietnamese IDAF-4C demonstrates good validity and reliability for assessing the multidimensional aspects of dental anxiety and fear. It is a suitable tool for clinicians and researchers in Vietnam to screen for dental anxiety and fear, which can help in developing tailored patient management strategies and more effective treatment plans.