The emergence of digital platforms disrupts the way we communicate, interact, and utilize ser-vices. We increasingly find ourselves in a world shifting away from Goods-Dominant (G-D) to-ward Service-Dominant (S-D) logic. One crucial aspect of this is the way we will use mobility in the future. In the past, we relied on goods in the form of privately owned cars to travel from point A to point B. However, platforms such as Uber, Lyft, DriveNow, and car2go change the way we use mobility from owning a car to using mobility as a service (MaaS). Although we have gathered knowledge about how to optimize production processes in the G-D world, how to de-sign successful platform ecosystems from an S-D perspective is unclear. In this article, we took a design science research approach to developing a framework that helps scholars to systematically compare, and practitioners to design, a mobility service platform ecosystem (MSPE). First, we started with a literature review to ground the artifact in S-D and MaaS re-search. We then developed the framework iteratively, drawing from literature and two case stud-ies representing a public and private mobility platform. The resulting artifact is a first step to-ward providing a structural, reproducible framework to design MSPEs that ensures comparabil-ity across platform ecosystems.