Soyuz 29 was a 1978 crewed Soviet space mission to the Salyut 6 space station. It was the fifth mission, the fourth successful docking, and the second long-duration crew for the orbiting station. Commander Vladimir Kovalyonok and flight engineer Aleksandr Ivanchenkov established a new space-endurance record of 139 days.

The crew returned in Soyuz 31, which had been swapped by a crew launched in August who returned in Soyuz 29.

This is Soyuz's 46th flight, and 28th 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.