Abstract
Background: The International Personality Item Pool–NEO–60 (IPIP–NEO–60) is an open-access personality inventory based on the Five-Factor Model (FFM). However, evidence on a culturally adapted and psychometrically evaluated Indonesian version remains limited. Objectives: This study aimed to cross-culturally adapt and psychometrically validate the Indonesian IPIP–NEO–60 among junior and senior high school students. Methods: A cross-sectional psychometric validation study involved 720 students aged 12–18 years, comprising 504 males (70.0%) and 216 females (30.0%). The instrument underwent forward and backward translation, multidisciplinary expert review, and cognitive interviews. Psychometric evaluation examined the hypothesised five-factor measurement model, internal consistency, convergent validity, and discriminant validity. Results: The measurement model showed an acceptable fit across several indices (RMSEA = 0.060, SRMR = 0.062, TLI = 0.952, CFI = 0.971). Standardised factor loadings ranged from 0.706 to 0.940. Cronbach’s alpha and composite reliability ranged from 0.950 to 0.969, indicating high internal consistency. Average variance extracted ranged from 0.615 to 0.731, supporting convergent validity. Discriminant validity was supported by the Fornell–Larcker criterion and Heterotrait–Monotrait ratios, with the highest HTMT value of 0.795. Conclusion: The findings provide preliminary psychometric evidence supporting the Indonesian adaptation of the IPIP–NEO–60 among junior and senior high school students in West Java and Banten. Further research should examine measurement invariance, temporal stability, and external criterion-related validity.