George Clark Haines, son of George Marvin Haines and his wife Octavia Louisa, born Goodrich, was an American entomologist. He joined the Division of Entomology of the South African Department of Agriculture on contract in 1912 to assist C.B. Hardenberg* with wattle bagworm investigations in Natal. He remained with the division for the rest of his career. For a number of years he was stationed at New Hanover, Natal, but during the nineteen-twenties he was at the headquarters of the division in Pretoria where he and D. Gunn* conducted general field and extension work and wrote useful pamphlets and circulars. He published articles on "The fig cuiculio" (1927) and "Cluster bugs" (1935) in Farming in South Africa, and contributed a paper on "Natural enemies and control of Bollworm in South Africa" to the Proceedings of the South and East African Agricultural Conference (Nairobi, 1927).
Haines was a member of the Pretoria Entomological Club, which was founded in May 1933 and was disbanded in 1936. In 1937 he became a foundation member of the Entomological Society of Southern Africa.