Robert Downs Haworth (15 March 1898 – 19 May 1990) was an English organic chemist.
He received his doctorate from Arthur Lapworth in 1922 at the University of Manchester and was a post-graduate student at the University of Oxford with William Henry Perkin Junior.
He researched the chemistry of natural products including resins, tannins, and the structure and synthesis of alkaloids.
A variant of the Friedel-Crafts alkylation, the Haworth reaction, is named after him (1932).
In 1956, he received the Davy medal "in recognition of his distinguished contributions to the chemistry of natural products particularly those containing heterocyclic systems".