In this chapter, I apply the concept of “normative agency” to NGO mediators promoting one of the salient and “buzziest” norms (Hellmüller, Conflict Intervention and Transformation: Theory and Practice. Rowman & Littlefield International, 2019) in contemporary peace mediation: the normative imperative of “inclusive peace.” First, I discuss how “inclusivity” has become a central topic of debate in literature on mediation. Second, through harnessing different conceptual approaches, I break down a mediator’s normative agency by inductively assessing the ability with which (1) NGO mediators can interpret norms in the normative frameworks outlined by their mandate-givers and frame them in certain ways to the negotiating parties, (2) NGO mediators engage in a set of practices that intentionally promote norms (their interpretation) and (3) NGO mediators wield the power to frame discourses and conduct these practices in the first place. Third, I discuss the limits of their normative agency and the risks of successful norm localization, as counterintuitive as that sounds. Multiple working definitions of inclusion being promoted by several NGO mediators working with negotiating parties with varying degrees of coordination and coherence may risk multiple interpretations of the norm, while also giving “recipients” the opportunity to reinterpret or redefine the norm in a way that appeals most to them.