Ronald George Wreyford Norrish FRS was a British chemist. He was born in Cambridge, England, and attended The Perse School and Emmanuel College, Cambridge. He was a former student of Eric Rideal. Norrish was a prisoner for part of World War I and later commented, with sadness, that many of his contemporaries and potential competitors at Cambridge had not survived the War.
Norrish rejoined Emmanuel College as a Research Fellow in 1925 and later became the Head of the Physical Chemistry Department at the University of Cambridge, occupying part of the Lensfield Road Building with the separate department 'Chemistry'. Both departments had separate administrative, technical and academic personnel until they merged to form one chemistry department under Sir John Meurig Thomas FRS in the early 1980s. Norrish researched photochemistry using continuous light sources. As a result of the development of flash photolysis, he was awarded the Nobel Prize in Chemistry in 1967 along with Manfred Eigen and George Porter for their study of extremely fast chemical reactions. One of his accomplishments is the development of the Norrish reaction.