This report, authored in partnership with the Institute for Security Studies (ISS), provides a detailed study of domestic practice of victim participation in criminal law proceedings. It analyses victims’ rights to engage in criminal proceedings and in particular the extent to which a range of domestic jurisdictions provide victims with rights to play an active role. Such rights may include the right to launch proceedings, to challenge decisions not to prosecute, and to make statements in court. The aim of this report is to support the efforts of states to develop and put in place a framework for victim participation in the context of investigating and prosecuting international crimes. This report aims to be a useful reference for actors in domestic systems engaged in wider discussions on victims’ rights.