While reviews of controlled studies of the Individual Placement and Support (IPS) model of supported employment for clients with severe mental illness have documented its effectiveness in the US, its generalizability to other countries has not been systematically evaluated. This is the first review to compare US to non-US studies. We identified 15 randomized controlled trials of IPS programs, 9 in the US and 6 outside the US. We examined competitive employment outcomes, including employment rate, days to first job, weeks worked during follow-up, and hours worked. We also considered noncompetitive employment, program retention, and nonvocational outcomes. IPS programs had significantly better outcomes across a range of competitive employment indicators and higher retention in services than control groups. The overall competitive employment rate for IPS clients in US studies was significantly higher than in non-US studies (62% vs. 47%). The consistently positive competitive employment outcomes strongly favoring IPS over a range of comparison programs in a group of international studies suggest that IPS is an evidence-based practice that may transport well into new settings as long as programs achieve high fidelity to the IPS model, but further research is needed on international adaptations.