Gwynfor Richard Evans (1 September 1912 – 21 April 2005) was a Welsh politician, lawyer and author. He was President of the Welsh political party Plaid Cymru for thirty six years and was the first Member of Parliament to represent it at Westminster, which he did twice, from 1966 to 1970, and again from 1974 to 1979.
Gwynfor Evans was born in Barry, near Cardiff, to Dan Evans and Catherine Richard. He had a brother named Alcwyn, and a sister named Ceridwen. His father ran a chain of shops in Barry, and his mother a china shop. His mother was a fluent Welsh speaker. As a boy, he was educated at Gladstone Road School. Later on he was educated at Barry County School, where he was captain of the school's cricket and hockey teams. At the school he began learning the Welsh language, but did not become fully fluent until the age of seventeen. He was educated at the University of Wales, Aberystwyth, and St John's College, Oxford, from where he qualified as a lawyer. During his time at St John's, he became a member of the Dafydd ap Gwilym society there. He was also a market gardener. He was a teenager when the Welsh nationalist party Plaid Cymru was founded in 1925, and he founded a branch of the party while he was at Oxford. He became the party's president in 1945 and retained the office until 1981.
A pacifist, he became active in Heddwchwyr Cymru, a Welsh organisation closely associated with the Peace Pledge Union, serving as secretary and editor of a series of pamphlets throughout the Second World War. A committed Christian also, he declared himself a conscientious objector, and was required to appear before a tribunal which, recognising the firmness of his beliefs, registered him unconditionally.
Evans is credited with keeping Plaid Cymru going through the lean years of the 1940s and 1950s. In the 1950s, he campaigned unsuccessfully for a Welsh parliament, and failed to prevent the damming of the Tryweryn River and consequent inundation of the Welsh-speaking community of Capel Celyn to supply the city of Liverpool with water, a cause célèbre in Wales in the early 1960s.