Lucius was the younger brother of the Gaius Valerius Flaccus who was consul in 93 BC;[REF] his son was the Lucius Valerius Flaccus (praetor 63 BC) who was defended by Cicero in the speech Pro Flacco.
Inscriptional evidence from Magnesia on the Maeander pertaining either to this Lucius Flaccus or to his son, who also was a governor of Asia, says he was married to a daughter of L. Saufeius and had a daughter named Valeria Paulla;[REF] his mother, a Baebia, is also commemorated.