William Milo Keynes, MD, FRCS (// KAYNZ; 9 August 1924 – 18 February 2009) was a British doctor and author. He was educated at Oundle and University of Cambridge.  He was the brother of Richard, Quentin and Stephen. He was interested in education and art, publishing books and essays about John Maynard Keynes, Isaac Newton, and the history of science. Upon his death he bequeathed a number of rare artworks to the University of Cambridge.
Milo was descended from a Cambridgeshire family that included both the lineage from two great families, the Keynes (of John Maynard Keynes) and Darwins (of Charles Darwin). He was the third son of Sir Geoffrey Keynes, and his wife Margaret Darwin, daughter of Sir George Darwin. He was a great-grandson of the world-renowned scientist Charles Darwin, and the nephew of the famous Cambridge economist John Maynard Keynes.
In 1983 Keynes edited a short collection of essays on his uncle and a biography of his uncle's wife, Lydia Lopokova. He also wrote books on the history of science, on Isaac Newton and on Mendelism in human genetics.
- Essays on John Maynard Keynes
- A Century of Mendelism in Human Genetics
- The Iconography of Sir Isaac Newton to 1800
- Lydia Lopokova. St. Martin's Press. 1983. ISBN 0312500394.
- Sir Francis Galton: The Legacy of His Ideas
- Evolutionary Studies: Centenary Celebration of the Life of Julian Huxley
- https://livesonline.rcseng.ac.uk/client/en_GB/lives/search/detailnonmodal/ent:$002f$002fSD_ASSET$002f0$002fSD_ASSET:373218/one?qu=%22rcs%3A+E001035%22&rt=false%7C%7C%7CIDENTIFIER%7C%7C%7CResource+Identifier - Biographical entry - Plarr's Lives of the Fellows Online]
- Keynes, William Milo - Biographical entry - Plarr's Lives of the Fellows Online
- Kraft, Robert (29 April 1984). "What He Saw In Her: LYDIA LOPOKOVA Edited by Milo Keynes.(book review)". New York Times. ProQuest 122403145.
- Annan, Gabriele (15 May 1983). "Everyone's Darling (book review)". The Observer. ProQuest 476834295.
- Oppenheimer, Peter (6 April 1975). "Keynes: Bloomsbury and beyond (book review)". The Observer. ProQuest 476273726.