British Nuclear Fuels Limited (BNFL) was a nuclear energy and fuels company owned by the UK Government. It was a manufacturer of nuclear fuel (notably MOX), ran reactors, generated and sold electricity, reprocessed and managed spent fuel (mainly at Sellafield), and decommissioned nuclear plants and other similar facilities.

It was created in February 1971 from the de-merger of the production division of the UK Atomic Energy Authority (UKAEA).

Until 2003, its headquarters were at Risley, near Warrington, England. BNFL's headquarters were then moved to Daresbury Park industrial estate, also near Warrington. On 1 April 2005, BNFL formed a new holding company and started a rigorous restructuring process which would transfer or sell most of its entire domain, divisions. In 2005, it transferred all of its nuclear sites to the Nuclear Decommissioning Authority. It then sold its Westinghouse Electric Company subsidiary in February 2006. Later, BNFL sold the separate companies that made up its major subsidiary, British Nuclear Group, leaving a decommissioning and reprocessing organisation which became Sellafield Ltd. By May 2009, BNFL had completed the sales of all its assets and had no remaining operational activities or businesses.

BNFL continued to exist only as a legal entity to meet all pension liabilities and any obligations arising from disposal programmes. However, on 14 October 2010, the Minister for the Cabinet Office, Francis Maude, announced that BNFL would be abolished along with a number of other government organisations.