Decentius


 * For the magister officiorum under Constantius II, see Decentius (magister officiorum).

Magnus Decentius (died 18 August 353) was a usurper of the Western Roman Empire against emperor Constantius II. American scholar Michael DiMaio speculates that Decentius possibly was the brother of Magnentius, who had revolted against Constantius on 18 January 350.

Magnentius elevated Decentius as Caesar by him that winter, to oversee the defence of Gaul and the Rhine frontier. He was appointed consul ordanarius in 352, and again in 353 with Magnentius.

When Magnentius was defeated by Constantius at the Battle of Mons Seleucus and committed suicide, Decentius, who was leading reinforcements, hanged himself at Senonae.