Abstarct: Abstract Covid19 disease not only threatens the physical health of individuals, but also causes multiple mental illnesses and endangers the mental health of individuals. This study aimed to investigate the impact of Covid 19 concerns on student-athletes' mental health with the modifying role of social support. This is a descxriptive-correlational study conducted using the field research method. Its statistical population consisted of student-athletes from Region 9 of Iran. Using G*Power, the statistical sample was determined 146 student-athletes selected by simple random sampling. Keyes Mental Health Questionnaire (2006) and the Social Support and Covid-19 Concerns Questionnaire (Graupensperger,2020) were used to collect data after their validity and reliability were confirmed. The collected data were analyzed using the partial least square (PLS) method and SPSS software was used to analyze statistical data.. The study revealed that Covid-19 concern has a significant negative impact on the student-athletes mental health. Social support also played a modifying role in the relationship between Covid19 concern and student-athletes' mental health and undermined this relationship. Moreover, the PLS-MGA results showed that there was no significant difference between the males and females. to strengthen social support and prevent the impact of Covid 19 concerns And its impact on student-athletes' mental health, university sports educators are recommended to continuously pursue the student-athletes' condition and university sports managers are recommended to help students' mental health by organizing sport events.