Bradwell-on-Sea is a village and civil parish in Essex, England. The village is on the Dengie peninsula. It is located about 9 km (5.6 mi) north-northeast of Southminster and is 30 km (19 mi) east from the county town of Chelmsford. The village is in the District of Maldon in the parliamentary constituency of Maldon whose boundaries were last varied at the 2010 general election. It has a population of 863, a decline from 877 in the previous census.

Bradwell-on-Sea was a Saxon Shore fort in Roman times known as Othona. The Anglo-Saxons originally called it Ithancester. Saint Cedd founded a monastery within the old walls in 653, which survives as the restored Chapel of St Peter-on-the-Wall, one of the oldest churches in Britain. From there, he continued the evangelisation of Essex. In the 20th century, the village became better known as the site for the Bradwell nuclear power station. It also has a very good sailing club and outdoor leisure facilities. There is a school - St Cedd's C. of E. Primary School.

The village has been called Bradwell juxta Mare, Bradwell-next-the-Sea and Bradwell near the Sea.

Celebrated residents include the Tudor martyr Thomas Abel, the newspaper editor Sir Henry Bate Dudley, the MP Tom Driberg, who is buried in the churchyard, and the artist F. H. Haagensen.

The local newspaper is the Maldon and Burnham Standard. There is a Facebook page called The Bradwell Bugle.