A major characteristic of pervasive computing applications is their ability to adapt themselves to changing execution environments and physical contexts. In this article, we analyze different kinds of adaptations and introduce a multidimensional classification for them. On this basis, we propose a novel approach for peerto-peer-based pervasive computing that provides support for the identified classes and integrates them in a multilevel architecture. We give a comprehensive overview of this architecture and its current realization in the Peer-to-Peer Pervasive Computing (3PC) project, discussing what adaptation is realized on each level, how the levels interact with each other, and how the overall system benefits from the integrated treatment of adaptation. ACM Reference Format:Handte, M., Schiele, G., Matjuntke, V., Becker, C., and Marrón, P. J. 2012. 3PC: System support for adaptive peer-to-peer pervasive computing.