A net-zero carbon future cannot happen without decarbonising buildings, since buildings and the construction sector account for nearly 40% of energy-related global CO2 emissions. The OECD project “Decarbonising Buildings in Cities and Regions” aims to identify best practices and challenges for both national and subnational governments in driving the decarbonisation of buildings. The project has started in 2021 with a multi-level governance framework to guide building policies, including energy efficient retrofits, installing high performance equipment and promoting renewable energy. Besides saving energy and reducing CO2 emissions, decarbonising buildings also brings multiple benefits such as reducing energy bills, improving health and creating green jobs. Using the framework as a foundation, the project provides more specific place-based analysis taking into account regional differences. The project can provide analysis of current bottlenecks in scaling up decarbonising measures and propose recommendations for both national and subnational policy makers.