The Oppian Hill is the southern spur of the Esquiline Hill, one of the Seven Hills of Rome, Italy. It is separated from the Cispius on the north by the valley of the Suburra, and from the Caelian Hill on the south by the valley of the Colosseum. The Oppius and the Cispius together form the Esquiline plateau just inside the line of the Servian Wall.
In the divisions of the Septimontium Fagutal appears as an independent locality, from which we can infer that originally "Oppius" was strictly applied to this spur except the western end. The northern tip of this western end was also called Carinae, which extended between the Velian Hill and the Clivus Pullius, looked out to the southwest, incorporated the Fagutal and was one of ancient Rome's most exclusive neighborhoods.
At least for religious purposes the name Oppius continued in use to the end of the republic; no later instance has been found. According to Varro its name derives from Oppius, a citizen of Tusculum who came to the Romans' assistance during Tullus Hostilius's siege of Veii. However, the word's true etymology is obscure. It may possibly be that of a clan that lived in this area, a gens name of plebeian status.