The main objective of this review was to assess the presently available evidence on the effects of interventions that aim to prevent and suppress trafficking in human beings. The search resulted in 144 potentially eligible studies. Most studies were in the field of sexual exploitation (68), or concerned several types of exploitation (55). The target group varied. It most often consisted of both adults and children (57), focusing on women and children, but studies on programs that were especially developed for minors (24) were found as well. The current landscape of anti-trafficking initiatives shows that many activities to combat trafficking have been initiated by numerous supranational, international as well as national organizations. In general, these organizations assess the prevalence and seriousness of the phenomenon and develop initiatives based on their findings. The aim of this systematic review was to explore what is known about the effectiveness of interventions that prevent or suppress cross-border trafficking for the purpose of sexual exploitation, in order to contribute to a more evidence-based approach in the prevention and suppression of cross-border trafficking for the purpose of sexual exploitation. The main conclusion is that there is no evaluation research on anti-trafficking initiatives that meets a strict research criteria. Consequently, no substantive conclusion about the effectiveness can be made, resulting in neither support nor rejection of the present anti-trafficking initiatives.