Obizzo III d'Este (14 July 1294 – 20 March 1352) was the Marquess of Ferrara from 1317 until his death.

Obizzo was lord of Ferrara with his brothers Rinaldo and Niccolò, and his cousin Folco II, but in the end reigned as sole ruler.

In May 1317, Obizzo married firstly Giacoma Pepoli (d. 1341), daughter of Romeo de' Peppoli from Bologna,[1][2] with whom he had no children.

In 1347, Obizzo married secondly Lippa Ariosti, known as la Bella, and his long-time mistress.

The marriage took place shortly before Lippa's death on 27 November 1347 to legitimize their many children:[3][4][better source needed] In addition, Obizzo had another illegitimate son by an unknown mistress, Giovanni (1324–1389), later Governor of Frignano, who was also legitimized.