Background: A systematic and comprehensive mental training program to enhance athletes’ mental toughness is critical. The aim of this study was to develop and validate a set of athletes’ systematic mental training programs. Methods: A mental toughness training program was developed, and the validity and reliability were tested on experts, practitioners, and athletes. Training program was analyzed using content validity index (I-CVI and S-CVI) and modified Kappa (k*). Furthermore, estimation of reliability of mental training model was analyzed by internal consistency approach with Cronbach’s alpha and inter-rater reliability (IRR) approach by using intraclass correlation coefficients (ICC). Result: A mental toughness training circle (MTTC) was successfully developed with four sections: general preparatory, specific preparatory, precompetitive, and competitive with 11 mental skills (positive thinking, mental log, goal-setting, breathing, relaxation, concentration, self-talk, mental imagery, leadership, managing anxiety, and managing emotions). Validation assessment found that the I-CVI and S-CVI values (S-CVI/Ave and S-CVI/UA) were 1.00, each suggesting excellent content validity. The modified Kappa value (k*) was 1 and categorized as excellent. The results of the reliability test using Cronbach's alpha showed that a value was in the range 0.723 to 0.835 with an overall value of 0.803. The results of the ICC analysis also confirmed that MTTC had a very high reliability coefficient value of 0.803. In addition, there was no significant difference from respondents’ assessment as proved by obtaining value of F=0.754 with a p=0.644 (>0.05). This suggested that respondents tend to be consistent in assessing MTTC as a mental training set which was categorized as relevant (scale 3) or very relevant (scale 4). Conclusion: MTTC which has four sections with 11 mental skills is a set of mental training programs that have high quality. Further studies to validate this program in a bigger sample size is required.