Joseph I Galesiotes (Greek: Ἰωσὴφ Α´ Γαλησιώτης; died 23 March 1283) was a Byzantine monk who served twice as Patriarch of Constantinople, from 1266 to 1275 and from 1282 until shortly before his death in 1283. He is most notable as an opponent of Emperor Michael VIII Palaiologos' plans to unite the Orthodox Church with the Catholic Church, for which he is recognized as a confessor by the Orthodox Church.