Sweyn I Forkbeard (c. 960 − 3 February 1014) is king of Denmark and England, as well as parts of Norway.

His name appears as Swegen in the Anglo-Saxon Chronicle.

He is a Viking leader and the father of Cnut the Great.

On his father Harald Bluetooth's death in late 986 or early 987, he becomes King of Denmark; in 1000, with allegiance of the Trondejarl, Eric of Lade, he is ruler over most of Norway.

After a long effort at conquest, and shortly before his death, in 1013 he becomes the first of the Danish Kings of England.