Samael (/ˈsæməˌɛl/; Hebrew: סַמָּאֵל, Sammāʾēl, "Venom of God"; Arabic: سمسمائيل, Samsama'il or سمائل, Samail; alternatively Smal, Smil, Samil, or Samiel) is an archangel in Talmudic and post-Talmudic tradition; a figure who is the accuser or adversary (Satan in the Book of Job), seducer, and destroying angel (in the Book of Exodus).

Although many of his functions resemble the Christian notion of Satan, to the point of being sometimes identified as a fallen angel, he is not necessarily evil, since his functions are also regarded as resulting in good, such as destroying sinners.

He is considered in Midrashic texts to be a member of the heavenly host with often grim and destructive duties. One of Samael's most significant roles in Jewish lore is that of the main angel of death and the head of satans. He appears frequently in the story of the Garden of Eden and engineered the fall of Adam and Eve with a snake in writings during the Second Temple period. However, the serpent is not a form of Samael, but a beast he rode like a camel. In a single account he is also believed to be the father of Cain, as well as the partner of Lilith. In early Talmudic and Midrashic literature, he has not yet been identified with Satan. Only in later Midrashim is he entitled "head of satans."

As guardian angel and prince of Rome, he is the archenemy of Israel. By the beginning of Jewish culture in Europe, Samael had been established as a representative of Christianity due to his identification with Rome.

In some Gnostic cosmologies, Samael's role as a source of evil became identified with the Demiurge, the creator of the material world. Although probably both accounts originate from the same source, the Gnostic development of Samael differs from the Jewish development of Samael, in which Samael is merely an angel and messenger of God.

Samael was first mentioned during the Second Temple period and immediately after its destruction. He is first mentioned in the Book of Enoch, which is a part of the Jewish apocrypha, along with other rebellious angels. In Enoch 1, he is one of the Watchers who descended to Earth to copulate with human women, although he is not their leader, this being Samyaza.

In the Greek Apocalypse of Baruch, he is the dominant evil figure. Samael plants the Tree of the knowledge of good and evil, thereupon he is banished and cursed by God. To take revenge, he tempts Adam and Eve into sin by taking the form of the serpent.

He appears further as the embodiment of evil in the Ascension of Isaiah and is called by various names: