The Global Observatory of Healthy and Sustainable Cities was initiated by the Global Healthy and Sustainable City-Indicators Collaboration to host the indicators developed for The Lancet Global Health series on Urban Design, Transport and Health. It involves a transdisciplinary and multi-organisational partnership among the People, Health and Place Unit of the Prevention Research Center, of the Brown School at Washington University in St. Louis, USA (website sponsor); the International Society of Physical Activity and Health (ISPAH); the International Society of Behavioral Nutrition and Physical Activity (ISBNPA); the International Society of Urban Health (ISUH); and the Executive Committee of the Global Healthy and Sustainable City-Indicators Collaboration.