To meet long-term climate goals, new and more aggressive approaches are needed to obtain substantial energy savings and reduce greenhouse gas emissions from existing buildings. Mandatory building performance standards are one such approach. We profile 17 jurisdictions of three types: those where standards are now being successfully implemented, those where implementation is just beginning or about to begin, and those where adoption is being considered. We summarize current trends across jurisdictions and draw preliminary conclusions. However, since implementation is just beginning, there is still much to learn on how best to structure and implement such policies in a way that provides quality housing and workplaces while also obtaining large energy savings and emissions reductions.