Grimoald (died 656, Paris) was a Carolingian mayor of the palace of Austrasia.
Grimoald succeeded his father, Pippin I of Landen, in 643 and for 13 years served under King Sigebert III. But, when the latter died in 656, Grimoald, rich and able, attracted sufficient partisans to consider that the time was ripe to supplant the Merovingians. He had Sigebert’s son and heir, Dagobert II, shorn of hair and packed off to an Irish monastery and then proclaimed his own son, Childebert the Adopted, king of Austrasia. The Austrasian aristocracy, however, reacted violently against him and his king, who was not of the blood royal. Grimoald, his son, and his brother-in-law Ansegisel were finally seized and turned over to the king of Neustria, Clovis II, who had them killed. The family disappeared from politics for about 14 years, until the rise of Ansegisel’s son, Pippin II of Herstal.