Over the last three decades, mediation processes have become more political and the role of international norms matters more than ever. For many who follow the field, the role of mediators shifted from peace-broker to a peacebuilder, especially in regard to whom they include in peace negotiations. So if mediators are pressured to promote norms, the more interesting question becomes: can they (Hellmüller, Sara, Julia Palmiano Federer, and Jamie Pring. 2017. Are mediators norm entrepreneurs? Bern: swisspeace. https://www.swisspeace.ch/assets/publications/downloads/Working-Papers/b59c7cb279/Are-Mediators-Norm-Entrepreneurs-17-swisspeace-sara_hellmueller-julia_palmiano_federer-jamie_pring.pdf. Accessed 14 December 2022.)? How does this work in practice and what are the consequences? In this chapter, I present an analytical framework around a mediator’s normative agency: the ability to which they can promote norms in the first place I start with a discussion of what norm diffusion theory (theories about how norms spread) have to say about mediators acting as norm entrepreneurs in peace processes.