Global information on the HIV/AIDS epidemic indicates the existence of an ever-increasing number of orphans and vulnerable children. It has been suggested that by the end of 2020 there will be more than 25 million AIDS orphans globally. However, there is a scarcity of reliable empirical data on the mental health of orphans and vulnerable children in the context of HIV/AIDS epidemic. This systematic review provides a synthesis of empirical findings related to mental Health of Orphans and Vulnerable Children within the context of HIV/AIDS in developing countries. A bibliographic database using keywords of the research area was searched on various databases, including Medline, PsychINFO and PsycARTICLES from 1980 to 2013. Twenty-eight (28) empirical quantitative studies were identified which addressed the mental health challenges of HIV AIDS orphans and vulnerable children. The studies are mainly cross- sectional with few longitudinal. Standardized measures were used in all of the studies reviewed. Findings show that, in the context of HIV/AIDS, children are found to suffer anxiety, worrying and fear during parental infection and to express trauma and grief after parental death. Compared to other children, orphans were observed to be more depressed, anxious, and less optimistic and to display angry feelings and disruptive behaviours. There is an urgent need for rigorous, research into mental health, and risk and protective factors for children affected by AIDS. The review findings also highlighted the need for an evidence-based, coordinated approach, interventions to promote the mental health of these children.