| Coordinates: | 51.7186°N -2.8064°W |
| Country: | Wales |
| Official Name: | Llansoy |
| Welsh Name: | Llan-soe |
| Static Image: | Llansoy.jpg |
| Static Image Width: | 250px |
| Static Image Caption: | Church of St. Tysoi at Llansoy |
| Unitary Wales: | Monmouthshire |
| Lieutenancy Wales: | Gwent |
| Constituency Welsh Assembly: | Monmouth |
| Constituency Westminster: | Monmouth |
| Post Town: | USK |
| Postcode Area: | NP |
| Postcode District: | NP15 |
| Dial Code: | 01291 |
| Os Grid Reference: | SO443025 |
Llansoy (cy|Llan-soe) is a small village in Monmouthshire, south east Wales, United Kingdom, located about 3 miles (4.2 km) south east of Raglan.
There is an Iron Age hillfort 1 mile (1.6 km) northwest of the village, at Great House, covering an area of about 5 acres (2 hectares) and overlooking the Olway Brook. Later, the area was reputedly settled by descendants of the Welsh king St. Brychan Brycheiniog.[1]
The parish church is believed to have been founded around the 6th century. The dedication is to Tysoi of whom nothing is known, although he is thought to have been a pupil of St. Dyfrig.[1] The church is largely built in the Perpendicular style of the 14th or 15th century, although the whole church was restored in 1858.[2] The tower probably dates from the late 17th century.[1]
The nearest pub, the Star Inn, is located about 1 mile (1.6 km) east of the village in the neighbouring parish of Llanfihangel Tor-y-Mynydd although its location is often given as Llansoy.