Wellington is a market town in Somerset, England. It is situated 7 miles (11 km) south west of Taunton, near the border with Devon, which runs along the Blackdown Hills to the south of the town. As well as the main built-up area of the town itself, the parish also includes the smaller settlements of Rockwell Green, Tone, and Tonedale. At the 2021 census, the Wellington built-up area had a population of 13,815, and the parish had a population of 16,678.

Known as Weolingtun in the Anglo-Saxon period, its name had changed to Walintone by the time of the Domesday Book of 1086. Wellington became a town under a royal charter of 1215 and during the Middle Ages it grew as a centre for trade on the road from Bristol to Exeter. Major rebuilding took place following a fire in the town in 1731, after which it became a centre for cloth-making. It is possible that the fire referred to here was actually in Tiverton, Devon which has details of a major fire in the same year. Further information on a major fire in Wellington at this time cannot be found.

In 1809, the Crown referenced Wellington when creating a viscountcy for the eventual Duke of Wellington, Arthur Wellesley, after his victory at the Battle of Talavera in the Peninsular War. When the title's name was being considered, Arthur's brother, Richard Wellesley, Earl of Mornington, found an available manor in the parish of Wellington, a name close to the family name. Richard oversaw the manor's purchase while Arthur commanded the army in Spain against the French. The Wellington Monument south of Wellington commemorates Arthur.

The Grand Western Canal reached the town in 1835 and then the Bristol and Exeter Railway in 1843. The town's own railway station survived until 1964. Wellington was home of Fox, Fowler and Company, which was the last commercial bank permitted to print their own sterling banknotes in England and Wales. In the 20th century closer links with Taunton meant that many of the residents of Wellington commuted there for work, and the M5 motorway enabled car journeys to be made more easily.

Local industries, which now include an aerosol factory and the Relyon bed manufacturers, are celebrated at the Wellington Museum in Fore street. Wellington is home to the independent Wellington School, and state-funded Court Fields School. It is also home to a range of cultural, sporting and religious sites including the 15th century Church of St John the Baptist.

The capital city of New Zealand is named after Arthur Wellesley, 1st Duke of Wellington, being recognised as having some influence in the company that founded the New Zealand town. The New Zealand capital therefore takes its name ultimately from the English town of Wellington in Somerset.

In a grant of between 899 and 909 Edward the Elder gave the land then known as Weolingtun to Bishop Asser, along with West Buckland and Bishops Lydeard. This was in exchange for the monastery of Plympton in Devon. The name may mean "the settlement in the temple clearing". By the time of the Domesday Book of 1086, the name had changed to Walintone and the estate was owned by Gisa, Bishop of Wells. The parish of Wellington was part of the Kilmersdon Hundred,

A site at Longforth Farm near Tonedale has been identified as having Bronze Age occupation and, during excavations prior to the building of new homes, found to have been occupied by a 12th-14th century building with decorated floor tiles covering 0.4 hectares (0.99 acres).