Chapter by Stefaan G. Verhulst and Sampriti Saxena: “Nearly 4.4 billion people, or about 55% of the world’s population, lived in cities in 2018. By 2045, this number is anticipated to grow to 6 billion. Such level of growth requires innovative and targeted urban solutions. By more effectively leveraging open data, cities can meet the needs of an ever-growing population in an effective and sustainable manner. This paper updates the previous contribution by Jean-Noé Landry, titled “Open Data and Urban Development” in the 2019 edition of The State of Open Data. It also aims to contribute to a further deepening of the Third Wave of Open Data, which highlights the significance of open data at the subnational level as a more direct and immediate response to the on-the-ground needs of citizens. It considers recent developments in how the use of, and approach to, open data has evolved within an urban development context. It seeks to discuss emerging applications of open data in cities, recent developments in open data infrastructure, governance and policies related to open data, and the future outlook of the role of open data in urbanization…(More)”.