Soyuz 27 was a 1978 Soviet crewed spacecraft which flew to the orbiting Salyut 6 space station, during the mission EP-1. It was the third crewed flight to the station, the second successful docking and the first visitation mission. Once docked, it marked the first time that three spacecraft were docked together.

The main function of the EP-1 mission was to swap Soyuz craft with the orbiting crew, in so doing freeing a docking port for a forthcoming supply tanker. Cosmonauts Vladimir Dzhanibekov and Oleg Makarov returned to Earth in the Soyuz 26 spacecraft after spending five days on the station.

This is Soyuz's 43th flight, and 26th crewed flight.

The Soyuz is a Soviet crewed spaceship, developed to made manned lunar missions. This version called 7K will fly 4 times on the giant launcher N1, and several tens of times on Proton to fly over the Moon, which will be successful during the mission Zond 4. Soyuz will become the first spacecraft to transport living beings to the Moon during the flight of Zond 5, with two turtles. Subsequently, it is adapted to low orbit and will fly on the Soyuz launcher to serve the Salyut and Mir stations and the ISS.