The Battle of Silva Arsia was a battle in 509 BC between the republican forces of ancient Rome on the one hand, and Etruscan forces of Tarquinii and Veii led by the deposed Roman king Lucius Tarquinius Superbus on the other. The battle took place nearby the Silva Arsia (the Arsian forest) in Roman territory, and resulted in victory to Rome but the death of one of her consuls, Lucius Junius Brutus.

The battle was one of a number of attempts by Tarquin to regain the throne, and can also be seen as part of ongoing conflict between the Etruscan cities and the expanding Roman state. The battle forms part of Rome's early history, which is probably in part legendary.

In 509 BC the Roman monarchy was overthrown, and the Roman Republic commenced with the election of the first consuls. The deposed king, Lucius Tarquinius Superbus, whose family originated from Tarquinii in Etruria, garnered the support of the Etruscan cities of Veii and Tarquinii, recalling to the former their regular losses of war and of land to the Roman state, and to the latter his family ties.