There is a dearth of research that investigates the relationship between religiosity and stigma of mental illnesses by the context of Jordanian culture. So, this study aimed to describe the relationship between religiosity and stigma against mental illnesses as described by undergraduate university students in Jordan. This study design was descriptive correlations study among 338 University Students, undergraduate students in Jordan. The findings indicate there is a significant correlation (r = - 0.154, p < 0.05) between stigma toward patient with mental illnesses and religiosity. The higher religiosity score is associated with more negativity toward stigma of patient with mental illnesses. Also, the findings indicated there was a significant difference between medical and non-medical student's specialty area and stigma toward patients with mental illnesses (t = 111.14, p = 0.01). Non-medical students reported more stigma for patients with mental illnesses. Stigma against patient with mental illnesses should be addressed at different levels. Cultural competency curriculum should be established for medical and non-medical students to assure more acceptance attitudes and avoidance of stigma against patients with mental illnesses.