OKB is a transliteration of the Russian initials for "Опытно-Конструкторское Бюро" (Opytno-Konstruktorskoye Byuro), which translates to "Experimental Design Bureau." During the Soviet era, OKBs were closed institutions working on design and prototyping of advanced technology, usually for military applications. The corresponding English language term for such a bureau's activity is R&D or "research and development." For security, each bureau was only officially identified by a number, but were often semi-officially referenced by the name of its lead designer. For example, OKB-51 was led by Pavel Sukhoi, and it eventually became known as simply Sukhoi. Successful and famous bureaus often retained these names after the departure of their founding designer. These relatively small state-run organisations were not intended for mass production of aircraft, rockets, or other vehicles or equipment which they designed. However, they usually had the facilities and resources to construct prototypes. Designs accepted by the state were then assigned to factories for mass production. After the collapse of the Soviet Union, many OKBs became Scientific Production Associations (NPOs). There were some attempts to merge them in the 1990s, and there were widespread amalgamations in 2001–2006 to create "national champion" corporations, such as Almaz-Antey to consolidate surface-to-air missile development.

OKBs in aerospace industry