How does the Office of the High Commissioner for Human Rights (OHCHR) discharge its mandate of "promoting and protecting the effective enjoyment by all of all civil, cultural, economic, political and social rights", especially in armed conflicts and other situations of violence? What are its concrete responsibilities, and how does it work to generate respect for the rule of law on the ground? This article aims to provide an overview of OHCHR's activities, and point to some of the challenges associated with its work to generate respect for the rule of law, in particular in violent contexts. It begins with an overview of the unique mandate of OHCHR and situates it within the broader United Nations human rights machinery. It then gives an account of OHCHR's experience and approach in building respect for the rule of law, including in armed conflicts and post-conflict situations, outlining how this informs OHCHR's field setup. Finally, the article summarizes the main challenges that OHCHR faces in the discharge of its mandate. It highlights the need for more concerted action on the part of human rights/humanitarian protection organizations on the ground, despite differences in mandates and constituencies. Keywords: OHCHR, human rights, prevention, rule of law, armed conflict, humanitarian law, High Commissioner for Human Rights.