Hengest or Hengist (d. 488?) was a semi-legendary ruler of Kent in southeast England.

The facts of his life are unknown, but according to Bede (writing nearly 200 years after the events in question), he and his brother Horsa were mercenaries for the British ruler Vortigern, hired to fight against the Picts. Following his victories over the Picts, Hengest invited more immigrants from Germany to settle in Britain and then rebelled against Vortigern, establishing himself as king in Kent.

Both Hengest and Horsa are described as being Jutes, and sons of a Jutish chief named Wihtgils.

The actual historical existence of both Hengest and Horsa has been called into question numerous times, with many historians labeling these two as legendary 'divine twins' along the order of Romulus and Remus. It is perhaps more likely that Hengest, meaning 'Stallion' in Old English (in modern German 'Hengst' is still the word for a stallion), was an honorific for an actual warlord, while Horsa was a later accretion to the story, perhaps as a misreading of a gloss in a manuscript that was written to define the name Hengest as meaning 'horse'.

Later accounts, in the Anglo-Saxon Chronicle, the Historia Britonum, by Geoffrey of Monmouth, and by Robert Wace add further details from tradition and legend about Hengest's career. The Anglo-Saxon Chronicle dates his death to 488, but does not provide a cause; according to some tellings of the Arthurian legend, he was killed by the British king Uther Pendragon.

Hengest is the subject of the 1620 play Hengist, King of Kent, or The Mayor of Queenborough by Thomas Middleton.

Hengest is also a character in the Fight at Finnsburg narrative mentioned in the Finnsburg Fragment and the Beowulf poem. In these texts, Hengest is a Danish warrior who takes control of the Danish forces after the prince Hnæf is killed, and succeeds in killing the Frisian lord Finn in revenge for his lord's death.

The events in these accounts had a historical basis, and have been supposed by historians to have occurred approximately 450 A.D. This makes these events contemporary with the Anglo-Saxon invasion of England, though what connection (if any) exists between the two Hengests is unknown.

Nevertheless, some have speculated that the two Hengests are one and the same. A point against this theory is the fact that one Hengest is described as a Jute and the other a Dane, though this does not serve as a conclusive disproof, as distinctions between adjacent groups (both Jutes and Danes lived in Denmark) were sometimes vague.