The United Kingdom possesses, or has possessed, a variety of weapons of mass destruction, including nuclear, biological, and chemical weapons. The United Kingdom is one of the five official nuclear weapon states under the Treaty on the Non-Proliferation of Nuclear Weapons. The UK renounced the use of chemical and biological weapons in 1956 and subsequently destroyed its general stocks.

A weapon of mass destruction (WMD) is a biological, chemical, radiological, nuclear, or any other weapon that can kill or significantly harm many people or cause great damage to artificial structures, natural structures, or the biosphere. The scope and usage of the term has evolved and been disputed, often signifying more politically than technically. Originally coined in reference to aerial bombing with chemical explosives during World War II, it has later come to refer to large-scale weaponry of warfare-related technologies, such as biological, chemical, radiological, or nuclear warfare.