De vulgari eloquentia (On Eloquence in the vernacular) is a short essay written by Dante Alighieri in Latin. The work remains incomplete; only one and a half books are extant.

It is believed to have been composed during Dante's exile, probably at some point between 1302 and 1305. The work revolves around the relationship between Latin and vernacular, and the need for a literary language, with an excourse on the poetic forms in vernacular. - Summary by Leni