Brjáns saga (also Brjánssaga) is a hypothetical early specimen of Old Norse literature. According to the hypothesis, certain episodes in Njáls saga and Þorsteins saga Síðu-Hallssonar drew on this lost saga. There is no external evidence of this saga's existence, though it was postulated by the Icelandic scholar Einar Ólafur Sveinsson, who edited Njál's saga in 1954. He believed it could have been written as early as the 1190s and used by the author of Orkneyinga saga, who wrote in about 1200.