Employers, insurers and workers have expressed a growing interest in workplace-based return-to-work (RTW) intervention studies. However, studies in this area have been scarce and have been conducted using a variety of research designs. At the request of the Workplace Safety & Insurance Board in Ontario, a systematic literature review of international studies published since 1990 in this area was conducted by the Institute for Work & Health to determine what makes RTW interventions effective. This report provides an overview of the findings from this systematic review.