Austrasia was the northeastern portion of the Kingdom of the Merovingian Franks, comprising parts of what are now eastern France, western Germany, Belgium, and the Netherlands. Its capital was at Metz, although some Austrasian kings ruled from Rheims also.

After the death of the Frankish king Clovis I in 511, his kingdom was partitioned among his four sons, Theuderic I receiving Austrasia. Austrasia and its neighbor, Neustria, were constantly at odds. These struggles reached their climax in the wars between Queen Brunhilda of Austrasia and Queen Fredegunde of Neustria. In 613, the king of Neustria, Clotaire II, took control of the other two kingdoms and a united Frankish kingdom was created with its capital in Paris.

With the weakening of royal power in Austrasia, the office of Mayor of the Palace developed into the real power in the kingdom, and finally became hereditary in the family of the Carolingians. Under this dynasty, Austrasia was no longer a separate kingdom.

For the rulers of Austrasia, see the list of Frankish Kings.