Religion has been generally considered as a protective factor for the psychological health of the people. As many studies have publicized a high prevalence of psychological morbidities among the medical students during their academic stages of medical schools, it is significant to investigate whether religiosity functions as a protective factor, to explore religiosity as a predictor of psychological well-being in a sample of medical students, and to compare the results of medical students as well as non-medical students with respect to religiosity and psychological well-being. The study is carried out in Federal Medical and Dental College and International Islamic University, Islamabad. The present study examined a sample of 120 medical students from Federal Medical and Dental College and 120 non-medical students from International Islamic University, Islamabad. Purposive sampling was used. The respondents completed religious orientation scale and scale of psychological well-being scale along with a demographic data sheet. In order to measure the study variables, linear regression and t test were used. The findings revealed that religiosity is a strong predictor of psychological well-being. Extrinsic and intrinsic religiosity predicts psychological well-being among the students. The results indicated a significant difference in psychological well-being between medical and non-medical students. No significant difference was found in religiosity of medical and non-medical students. The gender differences in religiosity and psychological well-being were found to be insignificant. The results emphasize that psychological well-being is prophesied by religiosity. The present research suggests further investigations and also endows with trends for psychological evaluation, development of religious beliefs, and interventions for augmenting psychological well-being among the medical students.