A Product Service System of Systems (PSSoS) is a set of products, services, infrastructure, and a network where its constituent elements exhibit operational and managerial independence. As such, a PSSoS shows PSS characteristics of heterogeneity and evolvability and SoS characteristics of emergence and diversity. Neither existing PSS nor SoS development approaches fully address these characteristics. Thus, PSSoS development raises new challenges. In this paper, we propose a PSSoS meta-model that integrates PSS and SoS key concepts, to provide a basis for future PSSoS development methods.