Decimus Junius Brutus Albinus (died 43 BC) was a Roman politician and general of the 1st century BC, one of Julius Caesar's assassins.

He was a legate in Julius Caesar army during the Gallic wars, but when the dictator returned to Rome after the final defeat of the Republican faction in the battle of Munda (45 BC), Decimus Brutus joined the group of conspirators that were planning his death. Apparently, Caesar continued to trust in him and, since he was a relative, mentioned him in the will he made in October 45. Moreover, in 44 BC, he was elected praetor by the centuriate assembly, by personal appointment of Caesar. Decimus Brutus was chosen to be praetor peregrinus and destined to be the governor of Italian Gaul in the following year.

On the Ides of March (March 15), the day of Caesar's assassination, Decimus Brutus accompanied the dictator in his morning appointments, prior to the senate meeting. His purpose was to send a signal to rest of the conspirators, waiting in the Forum. When Caesar arrived in Pompey's theatre, where the House was to meet, he was killed by the group, with Decimus among them.

The assassins received an amnesty in the next day, issued by the senate with the instigation of Mark Antony, Caesar's fellow consul. But the situation was not peaceful: Rome's population and the legionaries of Caesar's legions wanted to see the conspirators punished. The group decided to lie low and Decimus used his office of praetor peregrinus to stay away from Rome. The climate of reconciliation soon passed and slowly the conspirators were starting to feel the strain of the assassination. Thus, in the beginning of 43 BC, Decimus hurried to his province and started to levy his own troops. He was ordered by the senate to surrender his province to Antony but refused. This was the act of provocation to which Antony was only too happy to respond. With his own political situation on the verge of disaster, and himself declared public enemy, defeating Decimus was a way to regain his ascendance and get control of the powerful Italian Gaul. The first confrontation occurred in April 14, in the battle of Forum Gallorum , where Antony's troops besieged Decimus' army in Mutina. Antony was defeated by the forces of the consul Pansa and Octavianus, then only 19 years old but already a propraetor. A second battle on 21 April at Mutina resulted in a further defeat for Antony and a dead consul. Despite this luck, Decimus Brutus decided to flee to Macedonia, where Marcus Junius Brutus and Gaius Cassius Longinus were garrissoned. He left Italy, abandoning his legions, but was killed shortly afterwards, before reaching his fellow assassins.