Guildford /ˈɡɪlfərd/ is a large town in Surrey, England, located 27 miles southwest of central London on the A3 trunk road midway between the capital and Portsmouth. It is the seat of the borough of Guildford.

Guildford has Saxon roots and historians attribute its location to the existence of a gap in the North Downs where the River Wey was forded by the Harrow Way By AD 978 it was home to an early English Royal Mint. On the building of the Wey Navigation and Basingstoke Canal Guildford was connected to a network of waterways that aided its prosperity. In the 20th century, the University of Surrey and Guildford Cathedral, an Anglican cathedral, were added.

Due to recent development running north from Guildford, and linking to the Woking area, Guildford now officially forms the southwestern tip of the Greater London Built-up Area, as defined by the Office for National Statistics.