欧西里斯（Osiris 奥西烈斯，也作 Usiris 乌西里斯）是埃及神话中的冥王，九柱神之一，是古埃及最重要的神祇之一。他是一位反复重生的神，而他身上的绿色皮肤就有这种意思。他最后被埋在阿拜多斯（Abydos）城，是那里的守护神。

欧西里斯是大地之神盖布与天神努特的儿子。在埃及，欧西里斯是掌管阴间的神，同时也是生育之神和农业之神。他与妻子伊西斯生了荷鲁斯，另外奈芙蒂斯生了阿努比斯。与根据死者之书，他的长子叫做贝卜（Beb）。后来，他被同赛克和布塔联合起来成为「布塔-赛克-欧西里斯」，也被等同为赫里沙夫（Heryshaf）。

Osiris (/oʊˈsaɪərᵻs/, alternatively Ausir, Asiri or Ausar, among other spellings), was an Egyptian god, usually identified as the god of the afterlife, the underworld, and the dead, but more appropriately as the god of transition, resurrection, and regeneration. He was classically depicted as a green-skinned man with a pharaoh's beard, partially mummy-wrapped at the legs, wearing a distinctive crown with two large ostrich feathers at either side, and holding a symbolic crook and flail. Osiris was at times considered the oldest son of the earth god Geb, though other sources state his father is the sun-god Ra and the sky goddess Nut, as well as being brother and husband of Isis, with Horus being considered his posthumously begotten son. He was also associated with the epithet Khenti-Amentiu, meaning "Foremost of the Westerners", a reference to his kingship in the land of the dead. As ruler of the dead, Osiris was also sometimes called "king of the living": ancient Egyptians considered the blessed dead "the living ones". Osiris was considered the brother of Isis, Set, Nephthys, and Horus the Elder, and father of Horus the younger. Osiris is first attested in the middle of the Fifth dynasty of Egypt, although it is likely that he was worshipped much earlier; the Khenti-Amentiu epithet dates to at least the first dynasty, also as a pharaonic title. Most information available on the myths of Osiris is derived from allusions contained in the Pyramid Texts at the end of the Fifth Dynasty, later New Kingdom source documents such as the Shabaka Stone and the Contending of Horus and Seth, and much later, in narrative style from the writings of Greek authors including Plutarch and Diodorus Siculus.