Oleg Gazenko (b. December 12, 1918) is a Russian scientist and the former director of Institute of Biomedical Problems in Moscow. One of the leading scientists behind the Soviet animals in space programmes, he selected and trained Laika, the dog who flew on the Sputnik 2 mission. The mission provided no means for Laika to return home safely and she died within hours from overheating and stress.

In 1998 Gazenko expressed regret for allowing her to die in this manner, saying of Laika:

"Work with animals is a source of suffering to all of us. We treat them like babies who cannot speak. The more time passes, the more I’m sorry about it. We shouldn’t have done it. We did not learn enough from the mission to justify the death of the dog."