Laelius is a name that can refer to:
People Gaius Laelius, a Roman statesman, who was consul in 190 BC and friend of Scipio Africanus Gaius Laelius Sapiens (consul of 140 BC), a Roman statesman, son of the above, who was consul in 140 BC, and was friend to Scipio's adoptive grandson Scipio Aemilianus Decimus Laelius (tribune of the plebs 54 BC), one of the prosecutors Cicero opposed in the defense speech Pro Flacco Laelius Socinus, a 16th-century humanist and reformer
Literature Laelius de Amicitia, a philosophical dialog by Cicero on friendship, which is based on the second Gaius Laelius and his relationships with various great men Sir Robert Pipon Marett, a Jersey poet who used the pen name Laelius
Biology Laelius (wasp), genus of wasp from the subfamily Epyrinae, family Bethylidae