Decimus Laelius (born late-90s/early 80s BC) was a tribune of the plebs of the Roman Republic in 54 BC. In 59 BC, he was the lead prosecutor in the extortion case against L. Valerius Flaccus, who was defended by Cicero in the speech Pro Flacco. Laelius served under Pompeius Magnus as envoy and naval prefect in 49 and 48 BC, during the civil war against Julius Caesar. Cicero accuses him of bringing the case against Flaccus at the instigation of Pompeius.