This paper examines how institutional factors influence developments in the field of Mobility as a Service(MaaS). We draw upon neo-institutional theory in order to describe drivers and barriers of MaaS developmentsin Sweden and Finland. By analyzing similarities and differences across the cases, we identify a set ofgeneral implications for MaaS policymakers and practitioners. Developments in Finland demonstrate theimportance of top-level support, of inter-organizational collaboration and of trust among key stakeholders.The Swedish case reiterates the need for inter-sectorial collaboration, particularly with regard to creating theright conditions for commercialization, and to involving stakeholders on both strategic and operational levelsof the transport sector in developing the vision for MaaS. Lastly, we also assess the utility of the appliedtheoretical framework, and comment on the necessity of recognizing that both practice-based and structuralchanges are needed in order to facilitate institutional change.