Background: Socioeconomic status (SES) has often been considered a major predictor of mental health-related outcomes such as depression, anxiety, and stress. However, little is known about the mediating role of subjective social status (SSS) — an individual perception of relative position in the social hierarchy—in the relationship between SES and health outcomes. This study aimed to determine the mediating role of SSS in the relationship between SES and mental health among the employees of Tehran University of Medical Sciences (TUMS).Methods:The data from the enrolment phase of a cohort study on TUMS employees (n = 4461) were used in this cross-sectional study. Household SES was the main independent variable. SES was first entered into the mediation model as a composite index (a combination of wealth index, social class, and education), and then each indicator was entered separately. Stress, anxiety, and depression scores were measured using the DASS-42 Scale as a latent outcome variable for mental health status. SSS was evaluated as a potential mediator variable using the MacArthur scale which was converted to a five-point Likert item. The mediation analysis was carried out using a two-step structural equation modeling (SEM) approach in STATA version 14.0 with maximum likelihood (ML) estimation. Finally, the direct and indirect effects of SES indices on mental health were investigated, considering SSS's mediating role.Results: The data showed that 2706 participants (60.65%) were female and the mean age of all participants was 42.21±8.72 years. The standardized path coefficient for the direct effect of SES on SSS was --0.50 (SE=0.013), whereas the standardized path coefficient for the direct effect of SSS on mental health was 0.10 (SE=0.018). The standardized indirected effect of the composite SES-index on mental health through the SSS is -0.05 (lower SSS and mental health scores and higher SES scores indicate improvements in the status of these variables). Contribution of SSS in association between composite SES-index and the mental health of TUMS employees is 27.78% (27.27% in male and 22.23% in female). In addition, contribution of SSS for the association between the indices of wealth, education, social class and mental health is 41.67%, 36.36%, and 28.57%, respectively.Conclusions:The Findings of this study showed that a poorer SSS may influence the pathology of mental health disorders. It seems to be as a mediator in the association between SES and symptoms of depression, anxiety, and stress. Individuals' mental health may thus be improved by intervening in their subjective social status in relation to SES, which is relatively more stable.