Northiam is a village and civil parish in the Rother district, in East Sussex, England, 13 miles (21 km) north of Hastings in the valley of the River Rother. The A28 road to Ashford, Canterbury and Hastings passes through it.

Northiam has nine parish councillors elected by the village parishioners. The council usually meet once a month for a general meeting and sometimes twice a month if there are planning applications to be looked at. The Parish Council have an office at the Village Club in the centre of the village.

Rother District Council provides the next level of government with services such as refuse collection, planning consent, leisure amenities and council tax collection. Northiam lies within the Rother Levels ward, which provides two councillors.

East Sussex county council is the third tier of government, providing education, libraries and highway maintenance. Northiam falls within the Northern Rother ward.

The UK Parliament constituency for Northiam is Bexhill and Battle.

Prior to Brexit in 2020, the village was part of the South East England constituency in the European Parliament.

There is a Site of Special Scientific Interest within the parish. Officially designated as Northiam, it refers to a disused and partially flooded quarry on the outskirts of Northiam village. It is of geological, palaeoenvironmental and palaeogeographic interest.

The historic house Great Dixter is found within the village. Many parts of the village are listed including Frewen College (formally Brickwall House School), which is a day and boarding school for dyslexic children. It is believed to have been the first such school in the country, set up by Admiral Frewen. Centred on a Grade 1 listed Jacobean mansion named Brickwall after the extensive boundary walls, many period features have been retained in both the house and gardens.