Ragenfrid (also Ragenfred, Raganfrid, or Ragamfred) (died 731) was the mayor of the palace of Neustria and Burgundy from 715, when he filled the vacuum in Neustria caused by the death of Pepin of Heristal, until 718, when Charles Martel finally established himself over the whole Frankish kingdom.
His original centre of power was the Véxin. Dagobert III appointed him in opposition to Theudoald, grandson and heir of Pepin, and his grandmother Plectrude, but he was ignored by both Plectrude and Charles.
In 716, Ragenfrid and Dagobert's successor, Chilperic II, fought deep into the heartland of Arnulfing power: the Maas and Ardennes. They allied with Dagobert's old enemy, Duke Radbod of Frisia, and defeated their rival Charles near Cologne, in which he had been besieging Plectrude and Theudoald. Ragenfrid went and Chilperic forced Plectrude to surrender most of the Austrasian treasury, her grandson's claim to the mayoralty, and acknowledge Chilperic as king.
At this juncture, Charles set up his own Merovingian king, Clotaire IV; Dagobert's true successor, Chilperic II, being a staunch ally of Ragenfrid and the Neustrian nation. Ragenfrid and his king allied with Odo the Great, duke of Aquitaine independent since 715, but was defeated at Amel (north of St. Vith) in 716, and in March, 717, at Vincy, near Cambrai, and then in 718 at Soissons. Ragenfrid was now decisively out of power and he fled to Angers; however, he did not give up yet. When Paris and the Loire Valley were taken and Odo gave up Chilperic, who Charles finally accepted (under his thumb) in 719, Ragenfrid then gave himself up (720) and was deprived of his office, left only with lands in Anjou.
In 724, the Neustrians rebelled under Ragenfrid, but they were easily defeated. However, Ragenfrid gave up his sons as hostages in turn for keeping his county. He lived on until 731.