Background & Objectives: Gender dysphoria is defined as the sustained desire for or insistence on belonging to the opposite gender as well as considerable discomfort with the assigned sex and gender role. The present study aimed to examine the role of gender stereotypes (masculinity– femininity) in predicting the irrational beliefs and mental health of individuals with gender dysphoria. Methods: This was a descriptive and correlational study. The statistical population included all individuals with gender dysphoria, visiting the Iranian Legal Medicine Organization of Razavi Khorasan Province, Iran, from 2014 to 2016, to follow legal proceedings for gender reassignment. A hundred participants were selected via the convenience sampling method, provided informed consent, and completed Bem Sex– Role Inventory (BSRI), Jones Irrational Beliefs Questionnaire, and Goldberg Depression Questionnaire. All statistical steps were performed using SPSS. The obtained data were analyzed by Pearson’ s correlation coefficient and multiple regression analysis with a stepwise method. The significance level was set at 0. 05. Results: The present study findings suggested that males with gender dysphoria in femininity gender roles gained higher scores than females with gender dysphoria in masculinity gender roles. The correlation coefficient between irrational beliefs and masculinity was not significant (r=0. 04, p=0. 651). The correlation coefficient between several irrational beliefs, the need for others’ confirmation, high expectation, tendency to blame, response to failure, emotional irresponsibility, a great concern with anxiety, helplessness toward change, and perfectionism with the sexual role of positive women were significant (r=0. 39, p<0. 001). The correlation coefficient between mental health and femininity was positive and significant (r=0. 31, p=0. 002). The correlation coefficient between mental health and masculinity was positive and significant (r=0. 31, p<0. 001). The correlation coefficient between irrational beliefs and mental health (r=0. 54, p<0. 001) was positive and significant. Gender stereotypes predicted 17% of the variance of irrational beliefs in the samples with gender dysphoria (p<0. 001). Furthermore, gender stereotypes predicted 24% of the variance of mental health in the subjects with gender dysphoria (p<0. 001). The results of the comparison of two gender groups with gender dysphoria also revealed that the mean scores of men with gender dysphoria was higher in irrational beliefs, compared to those in women, which was not statistically significant concerning the t– value (p=0. 058). The results of the comparison of two gender groups with gender dysphoria also indicated that the mean scores of men with gender dysphoria was higher in mental health, compared to those in women, which was not statistically significant concerning the t– value (p=0. 480). Conclusion: Based on the current study findings, gender stereotypes could predict irrational beliefs and mental health in individuals with gender dysphoria. Therefore, the consideration of the variables derived from this research in therapeutic planning is necessary for those with gender dysphoria.