This study investigated the role of personality and loneliness in the mental health of undergraduate students. It examined the hypotheses that personality does not have a significant relationship with mental health (R2 = .55, ? = 23, t -.5.7). It also examined the hypotheses that loneliness will not have a significant relationship with mental health. One hundred and eighty (180) undergraduate students participated in this study. The mental health inventory, the big five personality inventory and loneliness scale were used for data collection. The collected data were subjected to multiple regression analysis. The result showed that loneliness does not have a significant relationship with mental health (Beta = 0.15, t =0.19). From the results and findings, the researcher observed that loneliness and personality do not predict mental health among undergraduate students. The implication of the findings indicates that clinicians should ensure they sharpen their skills in being able to identify the occurrence of loneliness as a psychological disorder in young adolescents since the disorder manifests early in life. Furthermore, efforts should be made by the mental health workers to sensitize the public in general and students’ in particular to the need to go for psychological assessment or treatment when they feel they have challenges with mental health-related issues. The Nigerian Association of Clinical Psychologists should endeavor to forward a recommendation to the government to make funds available to tertiary institutions across the country to establish psychological servicing centers at all the branches of the commission across the 36 states of the federation, including the FCT. It is recommended that for enhanced psychological well-being to be achieved in the country there should be a concerted effort to take a closer look into the role of loneliness and personality on the mental health of the most productive force in the economy, which is the youth.
Keywords: health, impact, loneliness, mental, personality, study, undergraduates