Evidence suggests the WHO Safe Communities model is effective in reducing injuries in whole populations. However, important methodological limitations exist in all studies from which evidence can be obtained. A lack of reported detail makes it unclear which factors facilitate or hinder a programme's success, and makes uncertain, whether the success of any particular application of the model is necessarily replicable in other communities. In evaluated programmes that did not report significant decreases in injury rates, this lack of information makes it difficult to distinguish between evidence of no effect of the model, or no evidence of effect. The four countries that have evaluated their Safe Communities with a sufficiently rigorous study design have higher economic wealth and health standards and lower injury rates than much of the world. No evaluations were available from other parts of the world, despite the designation of WHO Safe Communities in countries such as South Africa, Bangladesh, China, Vietnam, Canada, UK and USA. Generalisation of results of studies conducted in just four countries, to the international population needs to be done with caution. There is a need for more high-quality, methodologically strong evaluations of the model in a range of diverse communities and detailed reporting of implementation processes.