Velius Longus (2nd century AD), Latin grammarian during the reign of Trajan (or Hadrian), author of an extant treatise on orthography (H. Keil, Grammatici Latini, vii). He is mentioned by Macrobius (Saturnalia, iii.6.6) and Servius (Comm. on Aen. x.245) as a commentator on Virgil.