Theudebert II (French: Thibert ou Théodebert) (c.585-612), King of Austrasia (595-612 AD), was the son and heir of Childebert II. He received the kingdom of Austrasia plus the cities (civitates) of Poitiers, Tours, Le Puy-en-Velay, Bordeaux, and Châteaudun, as well as the Champagne, the Auvergne, and Transjurane Alemannia.
During his early years, his grandmother Brunhilda ruled for Theudebert and his brother Theuderic II, who had received the realm of Burgundy. After the two brothers reached adulthood, they were often at war, with Brunhilda siding with Theuderic. In 599, Theuderic defeated Theudebert at Sens, but then the two brothers allied against their cousin Chlothar II and defeated him at Dormelles (near Montereau), thereby laying their hands on a great portion of Neustria (600–604). At this point, however, the two brothers took up arms against each other; Theuderic defeated Theudebert at Étampes and he refused to aid his brother when Theuderic's kingdom was invaded by Clothar II in 605. In 610, he[who?] extorted Alsace from his brother and Theuderic took up arms against him, yet again.
Theudebert was defeated handily by Theuderic at Toul and at Zülpich in 612. Theudebert was locked up in a monastery at the order of his grandmother, and assassinated with his son Merovech.