The Kingdom of Essex or Kingdom of the East Saxons is one of the seven traditional kingdoms of the so-called Anglo-Saxon Heptarchy.

It is founded in the 6th century and covers the territory later occupied by the counties of Essex, Hertfordshire, Middlesex and (for a short while) Kent.

Kings of Essex are frequently subservient to foreign overlords.

The last king of Essex is Sigered and in 825, he cedes the kingdom to Egbert of Wessex.