The use of Private Security Companies (PSC) and Private Military Companies (PMC) for providing security services in conflict and post-conflict situations in many countries has been the subject of ongoing critical discussion among many scholars and media for many years. These companies are also operating in a post-conflict country such as Timor-Leste. However, they are not properly regulated and their number has been increasing since the country&rsquo;s independence in 1999. The thesis provides an assessment of the legal status and responsibilities of PSCs and PMCs, and their impact on Timor-Leste recovery efforts. In addition, the thesis proposes a proper legal framework to manage and regulate them under Timor-Leste national law.The methodology of this research is normative legal research, which is based on basic principles, norms, and regulations of legal frameworks. It uses primary and secondary data gathered from the Timor-Leste government, PSC offices in Timor-Leste, and United Nations documents relating to PSCs and PMCs. It also utilises cases and national legislations relating to the use of PSCs and PMCs from other countries, such as the United States, the United Kingdom, South Africa, and Indonesia.The research examines key legal issues, such as the regulation and monitoring of PSCs and PMCs, based on the principles and regulations of international law and the experiences of other countries relating to the use of PSCs and PMCs. In addition, it examines the impact of PSCs and PMCs on Timor-Leste national law and attempts to provide a possible proper regulation that can be used to manage and regulate these companies in Timor-Leste.This research focuses primarily on Timor-Leste and the impact of PSC and PMC operation for Timor-Leste society, legal system, and security improvement