William John Biffen, Baron Biffen, PC (born 3 November, 1930), is a Conservative member of the House of Lords. He was made a Life Peer in 1997.

He represented the constituency of Oswestry, later renamed Shropshire North, from the time of his election at a by-election in 1961 until his retirement immediately prior to the 1997 General Election.

In his early political career he was a disciple of Enoch Powell and championed tight fiscal policy and opposed state intervention in economic management. This stance barred his way to advancement under Edward Heath, but contributed to his promotion under Margaret Thatcher. He served in Mrs Thatcher's government in the successive positions of Chief Secretary to the Treasury, Secretary of State for Trade, and as Leader of the House of Commons.

Biffen's image as an economic dry mellowed during his time in government. His blunt public call for greater moderation in policy when he was called upon to respond to the government's loss in two by-elections in 1986, alienated him from Mrs Thatcher and resulted in his being dropped from the cabinet after the 1987 General Election.

|- style="text-align: center;" | width="30%" |Preceded by:
John Nott | width="40%" style="text-align: center;" |Secretary of State for Trade
1981–1982 | width="30%" |Succeeded by:
The Lord Cockfield