Dr John Frederick Vicars (sometimes Vickers) Phillips FRSE FRSS FLS (15 March 1899 – 17 January 1987) was a 20th-century South African botanist.
He served an apprenticeship in the South African Forestry Department and then won a bursary to study at the University of Edinburgh in Scotland.
He returned to South Africa as Forestry Officer in Deepwalls in Knysna undertaking ecological research on the indigenous forests.
Between 1985 and 1986 he led a United Nations Narcotics Bureau mission to northern Thailand and other far eastern countries to investigate drug-producing crops.
They had three daughters, Jean Dorothy, Marjory and Mary, and two sons, John Saunders Turnbull and Frederick Jan Smuts.