Sir Quentin Thomas (born 1944) is a former British civil servant, currently president of the British Board of Film Classification.

He attended the Perse School in Cambridge. He was a civil servant until 1999, serving in the Home Office, Northern Ireland Office and the Cabinet Office. His last civil service appointment was as Head of the Constitution Secretariat.

In the Northern Ireland Office from 1988 to 1998, he led the team which first met Sinn Féin following the 1994 cease fire. He led the team supporting Ministers in the 1996-98 roundtable talks, chaired by Senator George Mitchell, which culminated in the 1998 Good Friday Agreement. He was knighted in 1998 for “services to peace in Northern Ireland”.

In the Home Office he was Head of the Broadcasting Department 1984 to 1988), with responsibility for advising on the development of broadcasting policy, including cable and satellite broadcasting, and on relations between government and the broadcasting authorities and other regulatory bodies.