Lindsey or Linnuis is the name of the Anglo-Saxon kingdom that lay between the Humber and the Wash, forming its inland boundaries from the course of the Witham and Trent rivers (with the inclusion of an area inside of a marshy region south of the Humber known as the Isle of Axholme), and the Foss Dyke between them. It is believed that Lincoln was the capital of this kingdom.

Lindsey's greatest power was before the historical period. By the time of the first historical records of Lindsey, it had become a subjugated polity, under the alternating control of Northumbria and Mercia. All trace of its individuality vanished before the Viking assault. Its territories evolved into the historical English county of Lincolnshire, the northern part of which is called Lindsey.

A collection of genealogies, created in the last years of king Offa's reign, gives the names of the ruling lineage of Lindsey:

• Woden
• Winta: (Compare with Winteringham, the homestead of Winta's people, .)
• Cretta
• Queldgils
• Ceadbed
• Bubba
• Bedeca
• Biscop
• Eanferth
• Eatta
• Ealdfrith

Only the last individual (Ealdfrith) can be securely dated: Frank Stenton refers to an Anglo-Saxon charter (BCS 262) that mentions Ealdfrith, and dates its writing to some time between AD 787 and 796.