The gens Lartia, also spelled Larcia, or rarely Largia, was a patrician family at ancient Rome, whose members earned great distinction at the beginning of the Republic.
Spurius Larcius was one of the two companions of Horatius, who defended the Pons Sublicius against Lars Porsena in 508 BC.
A family of the same name existed in the late Republic and under the early Empire, but their relationship to the earlier Lartii is unknown.
The nomen Lartius is a patronymic surname, based on the Etruscan praenomen Lārs.
The nomen is always spelled Lartius in Livy, while Dionysius alternates between Larcius (Λάρκιος) and Largius (Λάργιος).