ABSTRACTIn this article, internationally supported peacebuilding is conceptualized as a cross-cultural relational endeavour, with international and local actors engaged in multiple forms of interactions in a local everyday context. Using a cultural-relational approach, two cases of peacebuilding are presented: Bougainville and Sierra Leone, which are at opposite poles of the spectrum of international-local peacebuilding interaction. Peacebuilding on Bougainville has drawn relatively little attention; the international intervention there was modest and small in size, and locals had considerable control of the peace process. By contrast, Sierra Leone is one of the best-known cases of peacebuilding, with massive external engagement and comprehensive external control. Both cases are considered success stories, but they differ considerably due to the differences in local-international relations. This is explained by focusing on two interrelated core aspects of the local-international interface: building relationships and trust, and security provision. Furthermore, another generally underestimated dimension of peacebuilding is explored, namely culturally different understandings of the spiritual realm and their effects on peacebuilding interventions.