Presents an obituary for Donald T. Stuss (1941–2019). The work of Donald T. Stuss, OC, FRSC, who died in Toronto on September 3, 2019, of complications following pancreatic cancer was world-leading but also notable for his influence on the landscape of Canadian neuroscience. Don worked as a teacher and football coach at high schools in Ontario before returning to the University of Ottawa to pursue graduate studies in psychology; he obtained his PhD in 1976. After a postdoctoral position at the Boston VA Medical Center, Don returned to Ottawa to pursue neuropsychological research at the university and also clinical work at the Ottawa General Hospital, where he served as director of clinical neuropsychological services from 1978 to 1989 and wrote the seminal volume The Frontal Lobes with Frank Benson (Stuss & Benson, 1986). Don had three major research interests in his scientific career: first, the functions of the frontal lobes and their role in cognitive processes, conscious awareness, and feelings of self; second, the effects of traumatic brain injury on these functions; and third, improving clinical approaches to assessment and rehabilitation. Each of these was grounded in Don’s thinking about functions of the frontal lobes in enabling cognitive processes and experiences in the normal adult, as well as how these functions are affected by focal and diffuse damage. Don’s success and influence as a researcher and scientific manager earned him many accolades and prestigious marks of recognition. These included being president of the International Neuropsychological Society, a member of the Order of Ontario, a Fellow of the Royal Society of Canada, and an Officer in the Order of Canada. Donald Stuss was a great neuropsychologist and also a great Canadian. (PsycINFO Database Record (c) 2020 APA, all rights reserved)