A vision is emerging of a connected world in which building equipment and systems coordinate with each other to efficiently meet their owners’ and occupants’ needs and buildings regularly transact business with other buildings and service providers (e.g., gas and electric service providers). While the technology to support this collaboration has been demonstrated at various degrees of maturity, the integration frameworks and ecosystems of products that support the ability to easily install, maintain, and evolve building systems and their equipment components are struggling to nurture the fledging business propositions of their proponents especially for small and medium commercial buildings. DOE is therefore sponsoring an effort to advance interoperability for the integration of intelligent buildings equipment and automation systems. As part of that effort, this report describes the current landscape of interoperability for connected buildings and outlines an initial list of requirements to be addressed going forward. In addition, it provides a summary of emerging information and communications technology (ICT) concepts that could advance interoperability for connected buildings.