In 2012, the United Nations approved new Guidelines on the Use of Armed Private Security Companies by its agencies, funds and programmes. The Guidelines hold the potential to not only enhance the quality of armed security services contracted by the un, but also raise professional standards within the military and security industry more generally by serving as a model for other consumers and companies. Nevertheless, a close reading of the Guidelines indicates that there is still room for improvements. Drawing on best practices identified by industry associations, major clients and academic research, this article makes six recommendations for revision. Specifically, the article contends that expanding the scope, content and enforcement of the Guidelines would contribute to strengthening the control over private security contractors.