This study aims to examine psychometrics of Turkish version of Mental Toughness Inventory (MTI) in Turkish elite athletes. MTI is developed by Gucciardi et al. (2014) and has eight items. 5 stages suggested by Beaton et al. (2000) was followed for the translation process. Three hundred athletes competing at different levels and sports were recruited for the study. Six experts in sport psychology were recruited to evaluate if the items in Turkish version were fit to assess mental toughness in sport. The main idea in seeking for content validity was to evaluate each item based on experts’ opinion whether the translated version was proper to assess mental toughness in sport. Structural equation modeling was used to test the construct validity of the inventory. By choosing the maximum likelihood method, the fit indexes of the scales were calculated. To test the measurement invariance of the Mental Toughness Inventory, measurement equivalence analysis was performed in the AMOS program. For Configural Invariance, where the factor numbers for men and women are considered equal, first, fit indices for the multi-group model without any restrictions were calculated. Second, limiting the invariance of factor loadings was calculated as metric invariance, scalar invariance was calculated by limiting means and intercepts. With the scalar invariance test, the mean sample variation because of common factors of MTI was tested. Strict invariance, which is calculated by constraining factor loadings, item regression constants (cut-off values), and residual variances, requires that these constraints be equivalent between groups In model comparisons, Δx2, Δdf, ΔCFI, ΔRMSEA, ΔSRMR values ​​were considered as fit indices. The cut-off points for these values ​​were used by Chen (2007) suggested intervals for small or unequal sample groups. For the partial invariance, intercepts which causes a significant change in chi square are relaxed for both groups. Consistency values for scales and sub-dimensions were calculated with the Cronbach's Alpha coefficient and McDonald’s Omega, while reliability values were calculated with composite reliability. The results of the analyses showed that the MTI is a valid and reliable measurement tool in elite Turkish athletes.