This article contributes to research on the relationship between multipolarity and multilateralism. One aim of this article is to consider the role of multilateralism in the age of multipolarity by investigating Russia's approach to multilateralism, especially in the context of the Donbas conflict. Russia has been a staunch supporter of a polycentric world order. Thus, an analysis of its attitude towards multilateralism provides insights into the role of multilateralism in the emerging multipolar world. It will be argued that, while convergence of interests and equal participation of states cannot be assumed in the age of multipolarity, multilateralism can still facilitate policy coordination among states, including rising powers, and provide legitimacy to their policy decisions. Another aim is to explore what peacekeepingan international practice reflective of multilateralismcan deliver in the multipolarising world. This article examines recent debates over the deployment of a peacekeeping mission to eastern Ukraine and argues that peacekeeping can not only help achieve security policy coordination among states, including rising powers, but also help create a common diplomatic culture and hence a sense of we-feeling among them, which may in turn develop into an inclusive regional security framework.