Guinea pig units used in pharmacology

Global processing unit, a generic name for a distributed computing project

Graphics processing unit, a special stream processor used in computer graphics hardware

Gosudarstvennoye Politicheskoye Upravlenie (Главное Политическое Управление, or Main Political Directorate) of the Red Army, responsible for troops morale and propaganda.

General Public Utilities, a defunct New Jersey-based electric utility purchased by First Energy Corporation in 2001, and famous as the original owners of the Three Mile Island nuclear plant.

The Global Peace and Unity event, an annual Muslim conference held at ExCeL Exhibition Centre in London.

Ground power unit, a device used on the ground at airports to supply aircraft without an APU with electric power. It is also used by aircraft with APUs if the airport authority does not permit the usage of APUs at its docks or if the carrier wishes to save on the use of jet fuel (which APU's use). The most common form of GPU is a small vehicle or trailer with a diesel generator although units fueled with gasoline are not unknown. There are also all-electric units that are powered off of the local electrical grid.

Gatwick Ports Unit, the Special Branch unit based at Gatwick Airport