Marcus Junius D. f. M. n. Silanus was consul in 25 BC with Gaius Julius Caesar Octavianus, the emperor Augustus.
Silanus was a descendant of the noble Roman house of the Junii Silani. He was probably the son of Decimus Junius Silanus, consul in 62 BC, and Servilia, and perhaps the grandson of Marcus Junius Silanus, consul in 109 BC. He was the brother-in-law of Marcus Aemilius Lepidus, the triumvir.
Silanus served as one of Julius Caesar's legates in 53 BC. He supported his brother-in-law Lepidus in 44 BC after Caesar's murder, accompanying Lepidus over the Alps. The following year, Lepidus sent him with a detachment of troops to join Marcus Antonius at Mutina, but refused to accept responsibility for the help which Silanus gave. After falling out of favor with the triumvirs, in 39 he fled to Sextus Pompeius. He was able to return to Antonius's service under the terms of the Pact of Misenum. Silanus later served under Antonius in Greece and Macedonia from 34 to 32, with the title of Quaestor pro consule or perhaps Proquaestor. Around this time he was also elected as an Augur.
Before the Battle of Actium, Silanus went over to Octavianus. The future emperor raised him to the Patriciate in 30 BC, and they held the consulship together in 25.
Silanus' grandson, Marcus Junius Silanus Torquatus, was consul in AD 19, and married a great-granddaughter of Augustus.