Christian Søren Marcus Olrik (13 October 1815 - 14 December 1870) was a Danish Greenlander professor, zoologist, botanist, and Royal Inspector of North Greenland.

He was the son of Vilhelm Mathias Olrik (1780-1833) and Lea Kirstine Geraae (1794-1828).

He returned to Greenland and was appointed Inspector of the North in 1846 after his brother-in-law, Hans Peter Christian Møller (1810-45) had died in office.

He was a popular contact for scientific expeditions to Greenland, as he was a trained and experienced botanist.

Three animal species are named after Olrik; a poacher, a tapeworm, and a leech.