Guy Coburn Robson (1888–1945) was a British zoologist, specializing in Mollusca, who first named and described Mesonychoteuthis hamiltoni, the colossal squid.

Robson studied at the marine biological station in Naples, and joined the staff of the Natural History Museum in 1911, becoming Deputy Keeper of the Zoology Department from 1931 to 1936.

Robson is best known for his major book The Variations of Animals in Nature (co-authored with O. W. Richards, 1936) which argued that although the fact of evolution is well established, the mechanisms are largely hypothetical and undemonstrated.^[1] The book claims that most differences among animal populations and related species are non-adaptive. It was published before major developments in the modern synthesis and contains critical evaluation of natural selection. It was positively reviewed in science journals in the 1930s.^[1][2] Zoologist Mark Ridley has noted that "Robson and Richards suggested that the differences between species are non-adaptive and have nothing to do with natural selection."^[3]

Historian Will Provine has commented that the book "has been in disrepute since the late 1940s because of its antagonism to natural selection" but notes that it was the "best known general work on animal taxonomy" before the work of Julian Huxley and Ernst Mayr.^[4] Huxley in Evolution: The Modern Synthesis (1942), described the book as "an undue belittling of the role of selection in evolution."^[5]

The following marine species have been named after Guy Robson to honour his contribution to science:^[6]

• Abralia robsoni Grimpe, 1931
• genus Robsonella W. Adam, 1938
• Onykia robsoni (Adam, 1962)
• Amphioctopus robsoni (Adam, 1941)
• Opisthoteuthis robsoni O'Shea, 1999
• Uroteuthis (Photololigo) robsoni (Alexeyev, 1992)
• Digitosepia robsoni (Massy, 1927)^[7]

• Guide to the Mollusca exhibited in the Zoological Department, British Museum (1923)
• The Species Problem (1926)
• A Monograph of the Recent Cephalopoda. Based on the collections in the British Museum, Natural History (two volumes, 1929–1932)
• The Variation of Animals in Nature (with O. W. Richards) (1936)

"In short, we do not believe that Natural Selection can be disregarded as a possible factor in evolution. Nevertheless, there is so little positive evidence in its favour, so much that appears to tell against it, and so much that is as yet inconclusive, that we have no right to assign to it the main causative role in evolution." (The Variation of Animals in Nature, 1936)^[8]