The gens Manlia (Classical Latin: [ˈmaːnlia]) was one of the oldest and noblest patrician houses at Rome, from the earliest days of the Republic until imperial times. The first of the gens to obtain the consulship was Gnaeus Manlius Cincinnatus, consul in 480 BC, and for nearly five centuries its members frequently held the most important magistracies. Many of them were distinguished statesmen and generals, and a number of prominent individuals under the Empire claimed the illustrious Manlii among their ancestors.[1]

The Manlii were said to hail from the ancient Latin city of Tusculum. The nomen Manlia may be a patronymic surname, based on the praenomen Manius, presumably the name of an ancestor of the gens.[2] The gens Manilia was derived from the same name, and its members are frequently confused with the Manlii, as are the Mallii.[1] However, Manius was not used by any of the Manlii in historical times. The Manlii were probably numbered amongst the gentes maiores, the greatest of the patrician families. As with many patrician gentes, the Manlii seem to have acquired plebeian branches as well, and one of the family was tribune of the plebs in the time of Cicero. The plebeian Manlii were probably descended from freedmen of the patricians, from members who had gone over to the plebeians, or from unrelated persons who acquired the nomen after obtaining the franchise from one of the Manlii.