Oliver Cummings Farrington (October 9, 1864 – November 2, 1933) was an American geologist.

[1] Between 1882 and 1887 he taught science in various Maine academies, in 1893 he was an assistant in the United States National Museum, in 1894 he became curator geology in the Field Museum of Natural History, Chicago, and from 1894 to 1904 he was lecturer on mineralogy at the University of Chicago.

He was a collaborator in mines and mineralogy at the Paris Exposition in 1900 and a member of the International Jury of Awards at St. Louis in 1904.

He was elected in 1909 a Fellow of the American Association for the Advancement of Science (AAAS).

[3] Besides his magazine articles, he was author of: The mineral farringtonite, first found in the Springwater meteorite, is named in his honor.