Leonine verse is a type of versification based on internal rhyme, and commonly used in Latin verse of the European Middle Ages. The invention of such conscious rhymes, foreign to Classical Latin poetry, is traditionally attributed to a probably apocryphal monk Leonius, who is supposed to be the author of a history of the Old Testament (Historia Sacra) preserved in the Bibliothèque Nationale of Paris. This "history" is composed in Latin verses which rhyme in the center. It is possible that this Leonius is the same person as Leoninus, a Benedictine musician of the twelfth century, in which case he would not have been the original inventor of the form. It is sometimes referred to disparagingly as "jangling verse" by classical purists, for example 19th century antiquaries, who consider it absurd and coarse and a corruption of and offensive to the high ideals of classical literature.

In English, the rhyme may be between a word within the line (often before a caesura) and the word at the end. Shakespeare used it to denote absurd characters, as in the speech of Caliban in The Tempest.