This report contains an overview of international law on unmanned and autonomous weapon systems. The report consists of three parts. First, a description of the international humanitarian law applicable to unmanned and autonomous weapon systems in armed conflict, as well as a description of human rights governing the use of unmanned and autonomous weapon systems in peace operations and other peacetime application. The report contains both rules on the use of such systems and rules on legal accountability. The report also outlines the legal method to be used in this type of analysis. The second part of the report describes the processes in certain state- and non-state fora and initiatives on the development of new international law on autonomous weapon systems. Most of the attention is focused on the work of the United Nation's group of governmental experts on the topic, CCW GGE LAWS, but also EU and NATO initiatives are mentioned. Third, the report contains an overview and analysis of the international legal research in the field since 2015. The report is concluded by suggestions on continued legal research in support of the development of autonomous weapon systems.