Kosmos 20 (Russian: Космос 20 meaning Cosmos 20) or Zenit-2 No.13 was a Soviet optical film-return reconnaissance satellite which was launched in 1963.

A Zenit-2 satellite, Kosmos 20 was the thirteenth of eighty-one such spacecraft to be launched.

In addition to reconnaissance, it was also used for research into radiation in support of the Vostok programme.

The launch took place at 09:36:00 GMT on 18 October 1963, using Site 1/5 at the Baikonur Cosmodrome.

Its return capsule descended under parachute and was recovered by the Soviet forces in the steppe in Kazakhstan.