Tregony (Cornish: Trerigoni), is a village in Cornwall, England, United Kingdom. Tregony was formerly a civil parish, but in 2021 it was merged with the neighbouring parish of Cuby to form a new parish called Tregony with Cuby. Tregony lies on the east bank of the River Fal, and is 6 miles (10 km) east of Truro. The Fal was historically navigable up to a port at Tregony. The village today has a shop with post office facilities, the Kings Arms pub, a sports and social club and two churches.

Tregony with Cuby parish also covers rural areas surrounding Tregony village, with several outlying farms. The part of the parish west of the River Fal was formerly the separate parish of Cornelly, which was absorbed into Tregony parish in 1934. At the 2021 census the population of Tregony with Cuby parish was 1,093 and the population of the Tregony built up area was 788.

The manor of Tregony was recorded in the Domesday Book (1086) when it was held by Frawin from Robert, Count of Mortain. Its earliest known spelling was Trefhrigoni, in 1049. There was 1 hide of land and land for 5 ploughs. There were 2 ploughs, 5 serfs, 3 villeins, 6 smallholders, 12 acres of woodland, 100 acres of pasture, 3 cattle, 40 sheep and 20 goats. The value of the manor was 15 shillings though it had formerly been worth 25 shillings.

Tregony was once a port, but clay mining upriver in St Austell has caused the river to become silted over.

Tregony was the birthplace of the Anglican churchman Archer Thompson Gurney. The Trewarthenick Estate in the hamlet of Trewarthenick in Cornelly parish, was the birthplace of William Gregor, a geologist-clergyman who discovered titanium. Captain William Hennah RN, who took part in the Battle of Trafalgar retired to Tregony and died there.

There are two tiers of local government covering Tregony with Cuby, at parish and unitary authority level: Tregony with Cuby Parish Council and Cornwall Council. The parish council meets at Tregony Village Hall on Back Lane.

Tregony was an ancient parish in the Powder Hundred of Cornwall. The original parish church, dedicated to St James, stood on the banks of the Fal at the western end of the parish. A chapel of ease dedicated to St Cuby was subsequently built in the 12th century to the north-east of Tregony, on higher ground and in a location which was more accessible for the rural parts of the parish. St James's Church was subsequently washed away by the changing course of the Fal in the 16th century. After that, the former chapel of St Cuby became the parish church. Following the loss of St James's Church there was some ambiguity about the name of the parish; in one court case in 1859 the parish was referred to as "St James and Cuby, otherwise Keby, otherwise Tregony, otherwise Tregony Martin, otherwise Tregony and Cuby".

By 1201, Tregony had become a borough. The borough boundaries just covered the western tip of the parish around the settlement itself, which at the time was a small town focused on its river port. The borough served as a constituency for parliamentary elections on a couple of occasions in the late 13th century and early 14th century, and again from 1559 onwards as the Tregony parliamentary borough, electing two members of parliament. The constituency was abolished under the Reform Act 1832.