Criminological literature on economic cybercrime has found that prevalence is rising rapidly, that public and private organisations dedicate considerable resources to combat the problem, and that the individual or end user is key to preventing victimisation. Given these three conclusions, it seems surprising that criminology has not dedicated more efforts to analyse what actually works to change human behaviours with regard to prevention. In order to provide a solid evidence base for future research and policy, the present study conducts a systematic review of literature from criminology, psychology and information technology, amongst others. Clear search terms and strict inclusion and exclusion criteria mean that the initial 7319 results from the bibliographical search of the most well- known academic databases were reduced to 96 studies. These studies all present quantitative findings on interventions that have attempted to change online behaviours with regard to economic cybercrime. By analysing the conclusions of the included studies and calculating their effect sizes, a number of interesting patterns begin to emerge. For example, we can see that interventions based on fear are not sufficient to change behaviour, or that generic one-off training has very little effect. On the other hand, we can see that the design of digital environments is particularly important for ‘nudging’ users to make safer choices. The findings should help organisations of all types make more informed decisions regarding their cybersecurity policies.