Dorking (/ˈdɔːrkɪŋ/) is a market town in Surrey in South East England about 21 mi (34 km) south-west of London. It is in Mole Valley District and the council headquarters are to the east of the centre. The High Street runs roughly east–west, parallel to the Pipp Brook and along the northern face of an outcrop of Lower Greensand. The town is surrounded on three sides by the Surrey Hills National Landscape and is close to Box Hill and Leith Hill.

The earliest archaeological evidence of human activity is from the Mesolithic and Neolithic periods, and there are several Bronze Age bowl barrows in the local area. The town may have been the site of a staging post on Stane Street during Roman times, however the name 'Dorking' suggests an Anglo-Saxon origin for the modern settlement. A market is thought to have been held at least weekly since early medieval times and was highly regarded for the poultry traded there. The Dorking breed of domestic chicken is named after the town.

The local economy thrived during Tudor times, but declined in the 17th century due to poor infrastructure and competition from neighbouring towns. During the early modern period many inhabitants were nonconformists, including the author, Daniel Defoe, who lived in Dorking as a child. Six of the Mayflower Pilgrims, including William Mullins and his daughter Priscilla, lived in the town before setting sail for the New World.

Dorking started to expand during the 18th and 19th centuries as transport links improved and farmland to the south of the centre was released for housebuilding. The new turnpike, and later the railways, facilitated the sale of lime produced in the town, but also attracted wealthier residents, who had had no previous connection to the area. Residential expansion continued in the first half of the 20th century, as the Deepdene and Denbies estates began to be broken up. Further development is now constrained by the Metropolitan Green Belt, which encircles the town.

The origins and meaning of the name Dorking are uncertain. Early spellings include Dorchinges (1086), Doreking (1138–47), Dorkinges (1180), and Dorkingg (1219). Both principal elements in the name are disputed. The first element may be from a personal name, Deorc, or some variant, of either Brittonic or Old English origin. Alternatively it may derive from the Brittonic words Dorce, a river name meaning "clear, bright stream", or duro, meaning a "fort", "walled town" or "gated place". The second element, if originally plural (‑ingas), might mean "(settlement belonging to the) followers of ...", but if singular (‑ing) might mean "place", "stream", "wood" or "clump".

Dorking is in central Surrey, about 21 mi (34 km) south of London and 10 mi (16 km) east of Guildford. It is close to the intersection of two valleys – the north-south Mole Gap (where the River Mole cuts through the North Downs) and the west–east Vale of Holmesdale (a narrow strip of low-lying land between the North Downs and the Greensand Ridge). The highest point in the town is the Glory Wood, south east of the centre, where the summit (137 m (449 ft)) is marked by a Bronze Age bowl barrow.

The basic plan of the town centre has not changed since medieval times (and may be Anglo-Saxon in origin). The main streets (the High Street, West Street and South Street) meet at Pump Corner, forming a " Y " shape. Together, West Street and the High Street run approximately west–east, paralleling the Pipp Brook, a tributary of the Mole, which runs to the north of the centre.

The town is surrounded by the Metropolitan Green Belt (which also covers the Glory Wood) and is bordered on three sides by the Surrey Hills National Landscape. Several Sites of Special Scientific Interest are close by, including the Mole Gap to Reigate Escarpment, immediately to the north. The National Trust owns several properties in the area, including Box Hill, Leith Hill Tower and Polesden Lacey.