A module used for the docking of two or more spacecraft.

When the Apollo and Soyuz vehicles docked during the Apollo–Soyuz Test Project in 1975, a special docking module was constructed to accommodate their different systems. It was 3.15 m long and 1.4 m in diameter. Serving as a passageway between the two spacecraft, it also contained a communication system and electric furnace for experiments.

A small docking module is known as a docking adapter. The docking adapter on the Skylab space station was joined to the Apollo command module, and had a second docking port in case a rescue vehicle had to be attached. The docking adapter also contained cameras and other instruments for observations of the Earth and Sun.