Psychometric properties of the Thai Mental Toughness Inventory (MTI-12): evidence from elite athletes in a Southeast Asian context

Introduction: Athletes’ psychological ability to maintain consistent performance under competitive pressure has often been described as mental toughness. The Mental Toughness Inventory (MTI) is perhaps the most widely used psychometric instrument for measuring athletes’ mental toughness. However, MTI’s factorial validity and measurement invariance have yet to be tested outside of Western sport settings. Objective: To confirm the factorial validity and reliability of the Thai MTI-12, assess measurement invariance across gender, age groups, sport type, and sport classification, and test for latent mean differences among groups. Method: Four hundred and eight Thai elite athletes (53.2% male; Mean Age = 22.52 years, SD = 5.93) from 32 sports participated. Confirmatory factor analysis and multi-group confirmatory factor analysis were conducted to assess factorial validity and measurement invariance. Results: Confirmatory factor analysis supported the hypothesized 12-item unidimensional model with good model-data fit. Multi-group confirmatory factor analyses revealed full scalar invariance across athlete groups. Latent mean analyses indicated that female athletes (ΔM = −0.27, p < .001) had significantly greater global mental toughness than males, and older athletes demonstrated higher goal commitment and stress regulation. Discussion: The Thai MTI-12 demonstrated strong factorial validity, supported its unidimensional factor structure, and showed scalar equivalence across athlete subgroups. Three culturally unique expressions of mental toughness emerged: collectivist obedience (kreng jai), perseverance through difficulty (khwam-othon), and Buddhist contemplative practices (equanimity and present-moment awareness). Conclusions: The Thai MTI-12 demonstrates strong psychometric properties and provides a culturally sensitive instrument for measuring mental toughness among elite Thai athletes and Southeast Asian populations.