Charles Ellicott Commentary 2 Kings 8:26

"Two and twenty years old was Ahaziah when he began to reign; and he reigned one year in Jerusalem. And his mother`s name was Athaliah the daughter of Omri king of Israel." — 2 Kings 8:26 (ASV)

Ahaziah. —Called Jehoahaz (2 Chronicles 21:17). Ewald thinks he assumed the name of Ahaziah on his accession.

The daughter of Omri — i.e., granddaughter. Omri is mentioned rather than Ahab as the founder of the dynasty, and the notorious example of its wickedness. (Compare Micah 6:16: The statutes of Omri are kept.)