Ahaz (Hebrew, "possessor") was king of Judah, and the son and successor of Jotham. Albright has dated his reign to 735 - 715 BC, while Thiele offers the dates 732 - 716 BC. His reign is described in 2 Kings 16; Isaiah 7-9; and 2 Chronicles 28.

He is said to have given himself up to a life of wickedness, introducing many pagan and idolatrous customs (Isa. 8:19; 38:8; 2 Kings 23:12). He ignored the remonstrances and warnings of the prophets Isaiah, Hosea, and Micah, and appealed to Tiglath-Pileser III, the king of Assyria, for help against Rezin , king of Damascus, and Pekah, Prince of Israel, who threatened Jerusalem, This brought a great injury of his kingdom, and his own humiliating subjection to the Assyrians (2 Kings 16:7, 9; 15:29).

He died at the age of 35, after reigning 16 years, and was succeeded by his son Hezekiah. Because of his wickedness he was "not brought into the sepulchre of the kings."