Harvey Reginald MacMillan, CC CBE (September 9, 1885 – February 9, 1976) was a Canadian forester, forestry industrialist, wartime administrator, and philanthropist. Born in Pine Orchard, Whitchurch Township, Ontario (today part of Whitchurch–Stouffville), he attended school in Bogarttown, Sharon, and Aurora. He graduated from the Ontario Agricultural College (then part of the University of Toronto) in 1906 with an honours degree in biology. He obtained a Master of Science degree in Forestry at Yale University in 1908. In 1912, he was appointed first Chief Forester of British Columbia.