Cosmos 381 (Russian: Космос 381) is a Soviet Kosmos equipped satellite. It was designed to research the outer spheres of the Earth and the cosmos around it. It was programmed by the Soviet Academy of Sciences. It was operated by the Defense Ministry of the Soviet Union (Russian: Министерство обороны – МО).
The main route of the orbital unit was an ellipse with an inclination of 104.80 minutes, 74.03 degree. It was a satellite with stabilised rounding, where it was stabilised with the Earth's magnetic sphere. It was 710 kilograms. Its energy was generated by a chemical rechargeable batteries. Time of its atmospheric entry is unknown.