Paul John Flory (June 19, 1910–September 9, 1985) was an American chemist and Nobel laureate who was known for his prodigious volume of work in the field of polymers, or macromolecules. He won the Nobel Prize in Chemistry in 1974 "for his fundamental achievements, both theoretical and experimental, in the physical chemistry of macromolecules."

After graduating from Elgin High School in Elgin, Illinois in 1927, Flory received a bachelor's degree from Manchester College (Indiana) in 1931 and a Ph.D. from the Ohio State University in 1934.
In 1938, after Carothers' death, Flory moved to the Basic Science Research Laboratory at the University of Cincinnati.
In 1940 he joined the Linden, NJ laboratory of the Standard Oil Development Company where he developed a statistical mechanical theory for polymer mixtures.
In 1943 he left to join the research laboratories of Goodyear as head of a group on polymer fundamentals.
He accepted a professorship at Stanford University in 1961, became the Jackson-Wood Professor there in 1966 and retired from there in 1975.