Dedham is a village within the borough of Colchester in northeast Essex, England, on the River Stour and the border of Essex and Suffolk. The nearest town to Dedham is the small market town of Manningtree.

Dedham is frequently rated as containing some of England's most beautiful Lowland landscape, most particularly the water meadows of the River Stour, which passes along the northern boundary of the village forming the boundary between Essex and Suffolk. Dedham has a central nuclear settlement around the Church and the junction of Mill Lane and the High Street (part of the B1029). Connected to Dedham are the hamlets of The Heath and Lamb Corner. The village forms a key part of the Dedham Vale.

Dedham is at the heart of 'Constable Country' - the area of England where Constable lived and painted. Constable attended the town's Grammar School (now the 'Old Grammar School' and 'Well House'), and he would walk to school each morning alongside the River Stour from his family's home in East Bergholt. Many of Constable's paintings feature Dedham, including Dedham Mill, which his father owned, and Dedham Parish Church, whose massive Caen stone and flint tower is a focal point of the surrounding Dedham Vale.

In 1937, Cedric Morris and Arthur Lett-Haines founded the East Anglian School of Painting and Drawing at Dedham. When, however, this burnt down, they moved to Hadleigh, Suffolk.

Of longer influence in Dedham was the horse painter Sir Alfred Munnings, who became President of the Royal Academy. His house in Dedham, Castle House, now contains a gallery of his work, and his studio.

Tom Keating, the art restorer and famous art forger, was a Dedham resident until his death in 1984. He is buried in the churchyard of St Mary's Church.