Sir John Grahame Douglas Clark (1907 -1995) was a British archaeologist most notable for his work on the Mesolithic and his theories on palaeoeconomy.

He was born in Bromley then in the English county of Kent but now part of London and educated at Marlborough and Peterhouse College, Cambridge. He spent his entire working career at Peterhouse save for his work in air photo interpretation for the RAF during the Second World War.

He became a fellow in 1950, Disney Professor of Archaeology two years later, head of the archaeology and anthropology department in 1956 and Master of Peterhouse from 1973 until 1980.

During his career he most famously studied the Mesolithic of northern Europe, excavating at Star Carr between 1949 and 1951, work which remains highly significant in our understanding of the period. He also wrote general works on world prehistory intended for a wide audience and encouraged archaeologists to more closely examine the economic factors relevant to past societies, characterised in his book Prehistoric Europe: the economic basis (1952).

He was also editor of the Proceedings of the Prehistoric Society and its President between 1958 and 1962. In 1951 he became a fellow of the British Academy, was made a CBE in 1971 and knighted in 1992.