Huyayy ibn Akhtab (Arabic: حيي بن أخطب; Hebrew: חי בן אחיטוב) was a chief of the Banu Nadir, a Jewish tribe of Medina in pre-Islamic Arabia.
His ancestry was Huyayy ibn Akhtab ibn Sa‘yah ibn Tha‘labah ibn ‘Ubayd ibn Ka‘b ibn al-Khazraj ibn Abi Habib ibn al-Nadir. He married Barra bint Samawal of the neighbouring Qurayza tribe: and had at least one son and two daughters with her. Barra bint Samawal was from distinguished Arabian Jewish family. Her father was the poet al Samaw'al ibn Adiya.
Huyayy is said to have been a "courageous warrior" and a "learned man".
According to his daughter, Huyayy opposed Muhammad from the day he arrived in Medina. She recalled:
At first Huyayy's opposition simply took the form of public debates. On one occasion, he had a discussion with Muhammad upon the mystical letters beginning some of the Surahs in the Quran. When a prominent rabbi, Abdullah ibn Salam, became a Muslim, Huyayy was one of those who said to him: "There are no prophets among the Arabs, but your master is an ordinary human king." When Abu Sufyan, the Quraysh leader and an enemy of Muhammad, presented himself before Huyayy's house, he, fearing to compromise himself, refused to admit him.
But Huyayy was to become the most inveterate enemy of Muhammad, to the point where ibn Hisham, Muhammad's biographer, calls him the enemy of Allah. In summer 625, Muhammad went to the Nadir quarter to ask them to contribute towards the army, secondary to Umayya's killing of two men from Banu Kilab. Huyayy agreed to give it to him, but as Muhammad was waiting by the wall of one of their houses their plan to assassinate him became apparent, he hurried away along with his companions and returned to Medina. When his followers asked him why he had left in such a hurry, He replied that the Angel Gabriel had warned him that Huyayy ibn Akhtab was urging the Jews to kill him and that 'Amr ibn Jahsh had volunteered to drop a rock onto his head.