This paper is intended to analyse two leading approaches that have guided international efforts to promote peace and development in conflict-affected fragile states since the 1990s, namely peace-building and state-building. In a relatively recent development, a growing number of donors has sought to bring these two closer together, based upon the perception that the challenges posed by (post-) conflict fragile states need to be addressed through an approach that combines both – “state-building for peace”, as the UNDP has put it. The paper thus seeks to explore how the processes of building peace are related to the processes of building more resilient, effective, and responsive states in (post-) conflict settings. The paper provides an overview of the evolution of these two concepts and analyses key complementarities between peace-building and state-building. It also explores the challenges that arise for both on the basis of these complementarities. The paper goes on to examine some of the most significant tensions that arise between the two, and what these tensions may imply for the international assistance community. By way of conclusion, the paper offers a few key lessons that emerge from the analysis for improved donor policy and practice in state-building for peace efforts.