Houyhnhnms are a race of intelligent horses described in the last part of Jonathan Swift's satiric Gulliver's Travels. The name can be pronounced Whin-hin-ems, as if 'whinny' were linked to the -nym element of, for example, 'synonym'.

Houyhnhnms contrast strongly with the Yahoos, savage humanoid creatures: whereas the Yahoos represent all that is bad about humans, Houyhnhnms have a stable, calm, and rational society. Gulliver much prefers the Houyhnhnm company over the Yahoo's, even though the latter are biologically closer to him.

This may be veiled criticism by Swift of the British Empire's treatment of non-whites as lesser humans, even though in many aspects their societies were equal or higher than the British.

Some of Jonathan Swift's dark vision affects the subtext of the movies Planet of the Apes.