The Global Community Technology Consortium (GCTC) is a smart cities program established by the National Institute of Standards and Technology (NIST), the research laboratory of the U.S. Department of Commerce. Since its formation in 2014, the GCTC has built an international partnership of cities and communities, private-sector entities, and government agencies dedicated to improving urban and rural ecosystems through integration of advanced digital technologies. Smart city standards are being developed in collaboration with the NIST Standards Coordination Office and guidelines established by the U.S. National Technology Transfer and Advancement Act (NTTAA) and relevant federal directives. This chapter describes the U.S standards development approach for the diverse communities, cities, regions, and governing jurisdictions within the United States, and presents the NIST approach for defining standards and metrics for smart cities.