Nils Johan Teodor Odhner (February 25, 1879 – October 29, 1928)[2] was a Swedish zoologist.

Odhner became an associate professor of zoology at Uppsala University in 1905,[4] a professor of zoology at the University of Oslo in 1914, a professor and curator of the Swedish Museum of Natural History in Stockholm in the invertebrate department in 1918,[5] and also director of the Stockholm Workers' Institute (Stockholms arbetareinstitut) in 1922.

[3][5] Odhner participated in Gustaf Kolthoff's zoological expeditions to Svalbard and eastern Greenland in 1900, and in Leonard Jägerskiöld expedition to the White Nile in 1901.

[3][5] He also conducted zoological studies at the stations in Trieste and Naples.

[5] He made several contributions to the literature on the anatomy and classification of the flukes, and in 1925 he was elected a member of the Royal Swedish Academy of Sciences,[5] where he served as vice secretary from 1923 to 1928.