This brief reviews and connects SEI’s recent work at the city scale on water resources, sanitation, climate, and sustainable lifestyles. Given the pace of urbanization, the development paths that cities take and how they use esources are critical issues for sustainability. SEI examines resource use in cities not only under under current conditions but also under different scenarios shaped by demographic and socio-economic trends, climate change, and key policy choices. SEI also provides analytical frameworks, tools and data for decision-makers at the municipal level, and places particular emphasis on equity in the urban environment and on the multiple levels of governance and policy that influence trends and outcomes at local scales. This brief presents key insights from this work, highlights major activities and key publications, and charts a path for future research.