The purpose of this paper is to shed light on the concept of MaaS and what characterizes a ‘MaaS service’,as well as to propose a topology of MaaS as a tool for facilitating the discussion of MaaS, enabling the‘comparison of’ different services, understanding MaaS’ potential effects, and aiding the integration ofsocietal goals into MaaS services. Based on a literature review analyzing existing definitions, and anexpert workshop identifying key aspects and ascertaining service differentiations accordingly, the resultingproposed topology consists of MaaS Levels 0 to 4 as characterized by different types of integration: 0 nointegration; 1 integration of information; 2 integration of booking and payment; 3 integration of the serviceoffer, including contracts and responsibilities; 4 integration of societal goals. The levels are described interms of their added value and further discussed regarding implications for business, society, users, andtechnical requirements. Then, a deeper discussion also delves into the potential in expanding upon Level 4and ways by which services and societal goals can become more fully integrated. The proposed topologyadds clarity to the discussion of such a trending topic and enables the positioning of services along theMaaS spectrum. It also deepens the understanding of why MaaS can take time to establish, and can helpsupport the development of action plans in terms of what needs to be done depending on what type ofMaaS one wants to develop. Further analysis is desirable regarding the possibilities and problems linkedwith the different levels of MaaS. Such an analysis is key to understanding which effects can be achievedvia the implementation of different levels of MaaS services in terms of e.g. social, economic and ecologicalsustainability, and business potential.