Kosmos 66 (Russian: Космос 66 meaning Cosmos 66) or Zenit-2 No.27 was a Soviet, first generation, low resolution, optical film-return reconnaissance satellite launched in 1965.

A Zenit-2 spacecraft, Kosmos 66 was the twenty-seventh of eighty-one such satellites to be launched[3][4] and had a mass of 4,730 kilograms (10,430 lb).

Kosmos 66 was launched by a Vostok-2 rocket, serial number R15002-04,[5] flying from Site 31/6 at the Baikonur Cosmodrome.

Kosmos 66 was operated in a low Earth orbit, on 7 May 1965 it had a perigee of 202 kilometres (126 mi), an apogee of 282 kilometres (175 mi), an inclination of 65.0° and an orbital period of 89.3 minutes.

On 15 May 1965, after eight days in orbit, the satellite was deorbited so that its return capsule could be recovered and its photos analysed, however, the mission was unsuccessful because a parachute deployment failed and the spacecraft was destroyed in the subsequent crash.