The 15th International Conference on Urban Regeneration and Sustainability addresses all aspects of the urban environment and aims to provide solutions leading towards sustainability. Urban areas result in a series of environmental challenges varying from the consumption of natural resources and the subsequent generation of waste and pollution, contributing to the development of social and economic imbalances. As cities continue to grow all over the world, these problems tend to become more acute and require the development of new solutions. The Sustainable City Conference addresses the multidisciplinary components of urban planning, the challenges presented by the increasing size of the cities, the amount of resources required and the complexity of modern society. The meeting always attracts a substantial number of contributions from participants from different backgrounds and countries. The variety of topics and experiences is one of the main reasons behind the success of the series. Topics The following list covers some of the topics to be presented at Sustainable City 2021. Papers on other subjects related to the objectives of the conference are also welcome. Urban strategies Planning, development and management Urban metabolism The community and the city The S3 city: smart, sustainable and safe Eco-town planning Spatial conflicts in the city Urban transportation and planning Architectural issues Cultural heritage sites Urban conservation and regeneration Environmental management Waste management Urban air pollution Health issues Water resources Landscape planning and design Urbanization of rural areas Urban agriculture Planning for risk and natural hazards Waterfront development Case studies