Cloud computing brings many benefits to information technology including cost savings, improved productivity, reduced maintenance, increased availability, and better user experiences. The North Atlantic Treaty Organization (NATO), the United States, and several member countries have introduced policies emphasizing a cloud-first approach for information technology. This move towards cloud computing has highlighted both benefits and struggles within defense programs. Modeling and Simulation (M&S) programs must address our unique constraints, objectives, business models, and policies in our use of cloud computing. In order to better understand the implications of cloud computing to M&S, the Simulation Interoperability Standards Organization (SISO) has established the Cloud-Based Modeling & Simulation (CBMS) Study Group (SG), which began in November 2016. The purpose of this study group is to identify and document existing M&S cloud activities, best practices, lessons learned, and potential standards in order to facilitate adoption by other practitioners. Cloud computing requires new technical architecture patterns for processing, communications, user interfaces, security policies, licensing considerations, and management, which is more than just moving legacy applications into virtual machines to execute on a remote server. This paper highlights findings from nearly two years of discussions, development, demonstrations, and lessons identified from applying key cloud concepts to M&S applications. The group’s activities are organized around twelve focus areas for examination and building knowledge and technology products as proof-of-concepts. The group has demonstrated working, composable services patterns, including deployment, orchestration, execution, and management of M&S services. We will present results from the group’s efforts including the successful composition and implementation of services within the cloud along with important considerations when executing simulation within the cloud.