Abstarct: The purpose of this study was the effect of motivational climate and social support on the mental well-being of young football plaxyers in Mazandaran province with the role of hope mediation. The method of the current research was descxriptive-correlative in nature and cross-sectional in terms of time. The statistical population of the research was all the young football athletes of Mazandaran province, 205 people were selected as a sample using random sampling method. The research tools were four standard questionnaires: Smith et al.'s motivational climate (2008), Zimmet et al.'s perceived social support (1988), Nkavandi et al.'s hope (2017) and Ryff's mental well-being (2002). Structural equations with variance-oriented approach were used to check the research hypotheses. SPSS23 and Smart-PLS 3.2.8 software were used for data analysis in the present study. The results of the research showed that the perceived social support and motivational climate had a positive and significant effect on the hope and mental well-being of football athletes, and hope has a positive and significant role on the mental well-being. The mediating role of hope in the relationship between perceived social support and mental well-being was confirmed, and also in the relationship between motivational climate and mental well-being, the component of hope plays a mediating role. According to the results of the research, it is suggested that educational workshops be held for parents and coaches to learn the necessary skills to prepare an environment where athletes can achieve success, to develop hope in them and to provide the basis for strengthening mental well-being.