Marcus Roscius Coelius (or Caelius) was a Roman military officer of the 1st century. He was the legate of the Legio XX Valeria Victrix, stationed in Britain in 68. He was on bad terms with the provincial governor, Marcus Trebellius Maximus, and took the opportunity during the turmoil of the year of four emperors to foment mutiny against him. Trebellius lost all authority with the army, which sided with Coelius, and fled to the protection of Vitellius in Germania. Coelius and his fellow legates briefly ruled the province until Vitellius, now emperor, sent Marcus Vettius Bolanus to be the new governor in late 69.