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. Rees taught at the University of British Columbia from 1969–70 until his retirement in 2011–12, but has since continued his writing and research. His primary interest is in public policy and planning relating to global environmental trends and the ecological conditions for sustainable socioeconomic development. He is the originator of the "ecological footprint" concept and co-developer of the method.