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 and had a mass of 4,720 kilograms (10,410 lb).
Kosmos 20 was operated in a low Earth orbit. On 18 October 1963 it had a perigee of 202 kilometres (126 mi) and an apogee of 296 kilometres (184 mi), with inclination of 64.8 degrees and an orbital period of 89.49 minutes. Having spent eight days in orbit, the spacecraft was deorbited on 26 October 1963. Its return capsule descended under parachute and was recovered by Soviet forces.
Payloads are separated by bullets ( · ), launches by pipes ( | ). Manned flights are indicated in bold text. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in brackets.