Gunnlaugs saga ormstungu () or the Saga of Gunnlaugr Serpent-Tongue is one of the Icelanders' sagas. Composed at the end of the 13th century, it is preserved complete in a slightly younger manuscript. It contains 25 verses of skaldic poetry attributed to the main characters. It is an important work in both Norwegian and Icelandic literary history. Gunnlaugr is sometimes Anglicized as Gunnlaug. The cognomen can also be translated as Worm-Tongue or Snake-Tongue.