Tarquinius (plural Tarquinii; compare the place name Tarquinia) is the gens name (nomen) of a Roman family of Etruscan origin. Two Tarquins were among the semi-legendary kings of Rome.

The names on the list of kings indicate that the Roman monarchy was not hereditary. The presence of two Tarquins, the last of whom was ousted as a tyrant, may indicate that the family attempted to monopolize power within the family contrary to Roman custom. According to tradition, the precipitating event was the rape of Lucretia by Sextus Tarquinius, the king son's. The expulsion of the Tarquins signaled the end of the Regal period and the beginning of the Republic in Roman history.

Read more about Tarquinius:  List of Tarquinii