Knightia is an extinct genus of clupeid clupeiform bony fish that lived in the fresh water lakes and rivers of North America during the Eocene epoch. The genus was erected by David Starr Jordan in 1907, in honor of the late University of Wyoming professor Wilbur Clinton Knight, "an indefatigable student of the paleontology of the Rocky Mountains." It is the state fossil of Wyoming, and the most commonly excavated fossil fish in the world.
Knightia is a small genus of the family Proteaceae endemic to New Zealand. One extant species, K. excelsa ( Rewarewa) is found in New Zealand, while a fossil species from upper Miocene deposits in Kaikorai has been described as Knightia oblonga. Two species from New Caledonia have been transferred to the genus Eucarpha by Lawrie Johnson and Barbara Briggs in their influential 1975 monograph "On the Proteaceae: the evolution and classification of a southern family".