The aim of this study is to examine the mediating role of self-esteem in university students in association with loneliness and psychological and subjective well-being. The study consisted of 340 university students, including 118 males and 222 females. The age range of participants is between 18 and 27. Rosenberg Self-Esteem Scale, Flourishing Scale, Satisfaction with Life Scale and UCLA Loneliness Scale were used in the study. Results of the study showed that loneliness was significantly and negatively associated with self-esteem, psychological well-being, and subjective well-being. Self-esteem was significantly and positively related to psychological well-being and subjective well-being. In this study, compared to male students, female students tended to report greater self-esteem, psychological and subjective well-being while they reported lower loneliness. Mediation analysis revealed that loneliness was a significant and negative predictor of self-esteem, psychological and subjective well-being. Self-esteem partially mediated the association between loneliness and well-being outcomes; and it significantly and positively predicted psychological wellbeing and subjective wellbeing. In university students, loneliness, and self-esteem, together, accounted for 38% of the variance in psychological well-being, while subjective well-being was 25%. Researchers can conduct new research to investigate the positive aspects of university students, and psychological counsellors working in schools can work towards strengthening the positive aspects of students.