Vulcacius Rufinus (died 368) was a Roman politician, related to the Constantinian dynasty.
A pagan, he was pontifex maximus, consularis for Numidia, comes ordinis primi intra consistorium under the Emperor Constans I or his brother Constantius II, comes per Orientem, Aegypti et Mesopotamiae per easdem vice sacra iudicans from 5 April 342, praetorian prefect of Italy from 344 to 347 (between the prefectures of Fulvius Placidus and Ulpius Limenius), consul ordinarius prior in 347 with Flavius Eusebius, and praetorian prefect of Illyricum between 347 and 352.
The usurper sent Rufinus, along with Marcellinus, Maximus and Nunechius, as envoys to Constantius II.
In 354, after the fall of Magnentius, he was praetorian prefect of Gaul, living in the capital Trier, but was replaced by Gaius Ceionius Rufius Volusianus Lampadius.
Rufinus may have lost his post because his relative Constantius Gallus had fallen into disgrace with the Emperor.