Northallerton  is a market town and civil parish near the River Wiske, North Yorkshire, England.

It is an administrative centre of the North Yorkshire District and has served as the county town of the North Riding of Yorkshire from 1889 to 1974 and of North Yorkshire from 1974 to 2023. The town lies in the Vale of Mowbray and at the northern end of the Vale of York. It had a population of 16,832 in the 2011 census an increase from 15,741 in 2001  Northallerton is made up of four wards: North, Broomfield, Romanby and Central.

There has been a settlement at Northallerton since Roman times; however, its growth in importance began in the 11th century when King William II gifted land to the Bishop of Durham. Under the Bishop’s authority Northallerton became an important religious centre. Later, it was a focus for much conflict between the English and the Scots, most notably the Battle of the Standard, fought nearby in 1138, which saw losses of as many as 12,000 men.

In later years trade and transport became more important. The surrounding area was discovered to have large phosphorus reserves. These brought industry to Northallerton due to the easy trade routes. Lying on the main route between Edinburgh and London, it became an important stopping point for coaches travelling the route, eventually superseded by the growth of the railways in the 19th century. Lying in the centre of a large rural area, Northallerton was established as a market town in 1200 by Royal Charter, and there is still a market in the town today.

It continues to be a major retail centre for the local area. As the administrative centre for the North Yorkshire Council, and several other associated public sector organisations have their headquarters in the town.