Marcus Furius Fusus was a consular tribune of the Roman Republic in 403 BC. Furius belonged to the Furia gens, an old and powerful patrician gentes of the Republic which had risen to become the most influential and powerful gens during the late 4th century BC with members such as Marcus Furius Camillus and Lucius Furius Medullinus. Furius seems to have been the son of Agrippa Furius Fusus, consul 446 BC or Gaius Furius Pacilus Fusus, consul 441 BC, and is not known to have had any prominent descendants himself.