George Hornidge Porter, Baron Porter of Luddenham, OM, FRS (6 December 1920–31 August 2002) was a British chemist.

He was educated at Thorne Grammar School, then won a scholarship to the University of Leeds and gained his first degree in chemistry.
Porter then went on to do research at Cambridge under Norrish where he began the work that ultimately led to them becoming Nobel Laureates.
His original research in developing the technique of flash photolysis to obtain information on short-lived molecular species provided the first evidence of free radicals. His later research utilised the technique to study the minutiae of the light reactions of photosynthesis, with particular regard to possible applications to a hydrogen economy, of which he was a strong advocate.
Porter became Fullerian Professor of Chemistry and Director of the Royal Institution in 1966. Porter was president of the Royal Society 1985–1990, having been elected a Fellow in 1960 and also winning the Davy Medal in 1971, the Rumford Medal in 1978, the Ellison-Cliffe Medal in 1991 and the Copley Medal in 1992. He was knighted in 1972 and was made a life peer as Baron Porter of Luddenham, of Luddenham in the County of Kent, in 1990.
Porter served as Chancellor of the University of Leicester between 1984 and 1995. In 2001, the University's chemistry building was named the George Porter Building in his honour.