William Rees, FRSC (born December 18, 1943), is Professor Emeritus at the University of British Columbia and former director of the School of Community and Regional Planning (SCARP) at UBC.

His primary interest is in public policy and planning relating to global environmental trends and the ecological conditions for sustainable socioeconomic development.

This research reveals the fundamental incompatibility between continued material economic growth and ecological security, and has helped to reopen debate on human carrying capacity as a consideration in sustainable development.

A dynamic speaker, Rees has been invited to lecture on areas of his expertise across Canada and the US, as well as in Australia, Austria, Belgium, China, Finland, France, Germany, Hungary, Japan, Mexico, the Netherlands, Norway, Indonesia, Italy, Korea, the former Soviet Union, Spain, Sri Lanka, Sweden and the UK.

[2] Rees has received a Dean's Medal of Distinction (UBC Faculty of Applied Science 2016) and the 2015 Herman Daly Award in Ecological Economics (USSEE).