an Iberian people living in what is now Portugal who resisted Roman penetration in the 2nd century BC. It is uncertain to what extent the Lusitani were Celticized, though they may have been related to the Celtic Lusones of northeastern Iberia. They first clashed with the Romans in 194 BC and joined the Celtiberians in a war against the Roman presence that lasted until 179 BC.

War broke out again in 153 BC, and under the leadership of Viriathus, an excellent strategist who managed to unite many Celtiberian tribes against the Romans, the Lusitani inflicted a series of defeats (c. 147–c. 139) on Roman troops from their military camp on the Hill of Venus (Sierra S. Vincente in Spain). After Viriathus was assassinated by his aides at Roman instigation, the Lusitanians were subdued. The name Lusitania was given to a Roman province later established (27 BC) in central Portugal.