Dual-use is a term often used in politics and diplomacy to refer to technology which can be used for both peaceful and military aims, usually in regard to the proliferation of nuclear weapons.

Many types of nuclear reactors produce fissile material, such as plutonium, as a by-product, which could be used in the development of a nuclear weapon. However, nuclear reactors can also be used for peaceful, civilian purposes: providing electricity to a city, for example. As such, a nation which wanted to develop a nuclear weapon could build a reactor, claiming it would be used for civilian purposes, and then use its plutonium to build a nuclear weapon. This is exactly what India did when developing its first atomic bomb in the 1960s, which sparked initiatives for stronger restraints on the trading of dual-use technology.

During the Cold War, the United States and the Soviet Union spent billions of dollars developing rocket technology which could carry humans into space (and even eventually to the moon). The knowledge gained from this peaceful rocket technology also served in the development of intercontinental ballistic missile technology as well.

The International Atomic Energy Agency attempts to monitor dual-use technology in countries who are signatories of the Nuclear Non-Proliferation Treaty, to make sure that fissile material is not diverted to military functions. In recent events, both Iran and North Korea have been accused of having nuclear weapons programs based on dual-use technology.

More generally speaking, dual-use can also refer to any technology which can satisfy more than one goal at any given time. Thus, expensive technologies which would otherwise only serve military purposes can also be utilized to benefit civilian commercial interests when not otherwise engaged.