Longus, sometimes Longos (Greek: Λόγγος), was the author of an ancient Greek novel or romance, Daphnis and Chloe. Very little is known of his life, and it is assumed that he lived on the isle of Lesbos (setting for Daphnis and Chloe) during the 2nd century AD

It has been suggested that the name Longus is merely a misinterpretation of the last word of Daphnis and Chloe 's title Λεσβιακῶν ἐρωτικῶν λόγοι δ' in the Florentine manuscript; Seiler also observes that the best manuscript begins and ends with λόγου (not λόγγου) ποιμενικῶν. If his name was really Longus, he was probably a freedman of some Roman family which bore that name as a cognomen.