Nearly one-quarter of the refugees worldwide are children. There have been numerous studies reporting their levels of psychological distress. The aim of this paper is to review systematically and synthesize the epidemiological research concerning the mental health of refugee children residing in Western countries. A Cochrane Collaboration style review was conducted searching nine major databases, bibliographies, and grey literature from 2003 to 2008. Included studies had to meet the reporting standards of STROBE and investigate mental health in non-clinical samples of asylum seeking and refugee children residing in OECD countries. A total of twenty-two studies were identified of 4,807 retrieved citations, covering 3,003 children from over 40 countries. Studies varied in definition and measurement of problems, which included levels of post-traumatic stress disorder from 19 to 54%, depression from 3 to 30%, and varying degrees of emotional and behavioral problems. Significant factors influencing levels of distress appear to include demographic variables, cumulative traumatic pre-migration experiences, and post-migration stressors. Importantly, the research base demands greater contextual and methodological refining such that future research would have greater generalizability and clinical implications.