In this chapter, I describe the emergence of NGO mediators in peace mediation. To avoid confusion regarding the unit of analysis, I focus on the normative frameworks and normative socializations of NGO mediators primarily as institutions, and not individuals. While the normative agency of NGOs as institutions and individuals may be closely interlinked, assessing the normative agency of individuals employed by NGOs require psychological and sociological methodologies that fall beyond the scope of this bookI view NGO mediators as private actors who take on discreet or public mediative or facilitative functions or activities among and between the negotiating parties in a peace process (Palmiano Federer, Rethinking Peace Mediation: Challenges of Contemporary Peacemaking Practice. Bristol University Press, 2021) The unit of analysis I focus on are international NGOs (INGOs) rather than local or national peacemaking organizations. While NGO mediators are seen to have little political power, they wield distinct characteristics such as moral authority, informality and the ability to partner within their institutional structure. These characteristics imbue them with an alternative type of legitimacy that lends to certain comparative advantages vis-à-vis other types of mediators. I also suggest that there are three types of NGO mediators, the “local-insider,” the “regional-outsider” and the “international modular.” All of these aspects contribute to NGO mediators’ “normative socializations” (Hellmüller et al. 2015), which are the highly subjective way that a mediation actor interprets a norm, based on their own personal view, which in turn affects their ability to promote norms to negotiating parties in peace processes.