Swanbourne is a village and civil parish in Buckinghamshire, England, two miles (3.2 km) east of Winslow and three miles (4.8 km) west of Stewkley.

The village name is Anglo Saxon in origin and may mean "swan stream". It was recorded as Suanaburna in the Anglo-Saxon Chronicle in 792.

A grant of land was made to Woburn Abbey in 1201. The first vicar of the parish arrived in 1218 and the parish church was dedicated in 1230. The abbey was dissolved in 1538 and its lands were later sold by the Crown.

Swanbourne people supported Parliament in the English Civil War. It was burnt down by Royalist troops in 1643. The Aylesbury–Buckingham turnpike road through Swanbourne opened in 1722. Common lands were enclosed in 1762–1763 and divided among 50 landowners.

Swanbourne House was bought in 1798 by Thomas Fremantle (1765–1819) for his wife Elizabeth, known as Betsey, for 900 guineas. The Fremantle family, originally from Aston Abbotts, had strong naval connections. Their eldest son Sir Thomas Francis Fremantle (1798–1890) became a prominent Tory politician. Their second son Charles (1800–1869) followed his father into the British Royal Navy and was instrumental in founding the Swan River Colony in Western Australia, which accounts for the place names Fremantle, Swanbourne and Cottesloe in the Perth area. Another son, Captain Stephen Grenville Fremantle is also buried in the churchyard.

Swanbourne House is still owned by the Fremantle family trust, but it is let to the private Swanbourne House School. The present head of the family is Commander John Tapling Fremantle, 5th Baron Cottesloe, a former Lord Lieutenant of Buckinghamshire. He lives in the village, as does his daughter Elizabeth, the Hon. Mrs Duncan Smith, with her husband Iain Duncan Smith, a Conservative politician.

There was an agricultural strike in Swanbourne in 1873, led by some members of the Primitive Methodist Chapel, who had joined the National Agricultural Labourers' Union.

Attached to the village is the hamlet of Nearton End.