Sir Derek Harold Richard Barton FRS (8 September 1918–16 March 1998) was a British organic chemist and Nobel Prize laureate.

Barton attended Tonbridge School and in 1938 he entered Imperial College London, where he graduated in 1940 and obtained his Ph.D. degree in Organic Chemistry in 1942.
During 1949 and 1950 he was Visiting Lecturer in the Chemistry of Natural Products, at Harvard University, and was then appointed Reader in Organic Chemistry and, in 1953, Professor at Birkbeck College.
In 1950, Professor Barton showed that organic molecules could be assigned a preferred conformation based upon results accumulated by chemical physicists, in particular by Odd Hassel. Using this new technique of conformational analysis, he later determined the geometry of many other natural product molecules.
In 1969, Barton shared the Nobel Prize in Chemistry with Odd Hassel for "contributions to the development of the concept of conformation and its application in chemistry."
In 1978 he became Director of the Institut de Chimie des Substances Naturelles (ICSN - Gif Sur-Yvette) in France.
In 1986 he became Distinguished Professor at Texas A&M and held this position for 12 years until his death.
He died in College Station, Texas.