Konstanty Roman Jelski (Belarusian: Канстанцін Ельскі, February 17, 1837 – November 26, 1896) was an acclaimed Polish ornithologist and zoologist who explored French Guiana.

Jeski was born in Liady village, now in the Smalyavichy Raion of Minsk Governorate (in present-day Belarus), to Michał and Klotilda.

Here he received help from Rustem Bey (of Polish descent) and took part in a government effort to explore geological resources.

He found that all they wanted were superficial reports and he then moved to France and came in contact with the natural history specimen traders Maison Verreaux and Deyrolle.

[2][3] Jelski married Helena née Korsak in 1883 and they had four children, two died young while a son and daughter were killed by the Soviets in 1939.