| Country: | Wales |
| Coordinates: | 51.71°N -4.75°W |
| Official Name: | East Williamston |
| Population: | 1844 |
| Population Ref: | (2011)[1] |
| Unitary Wales: | Pembrokeshire |
| Constituency Westminster: | Carmarthen West and South Pembrokeshire |
| Constituency Welsh Assembly: | Carmarthen West and South Pembrokeshire |
| Post Town: | KILGETTY |
| Postcode District: | SA68 |
| Postcode Area: | SA |
| Post Town1: | SAUNDERSFOOT |
| Postcode District1: | SA69 |
| Postcode Area1: | SA |
| Post Town2: | TENBY |
| Postcode District2: | SA70 |
| Postcode Area2: | SA |
| Os Grid Reference: | SN097050 |
East Williamston (Welsh: Tregwilym Ddwyrain) is a village and community in Pembrokeshire, Wales. The community includes the villages of Pentlepoir, Cold Inn and Broadmoor, Wooden and Moreton. The community had a population of 1,787 in 2001, increasing to 1,844 at the 2011 Census.
With the community of Jeffreyston, it makes up the Pembrokeshire electoral ward of East Williamston, which had a population of 2,327 in 2001, with 11 per cent Welsh speakers. The ward population had increased to 2,418 at the 2011 Census.[2]
It was originally a chapelry of the parish of Begelly.[3]
Its census populations were: 341 (1801), 551 (1851), 397 (1901), 387 (1951), 473 (1981).
The percentage of Welsh speakers was 5% cent (1891), 12% (1931), 3% (1971), 11% (2011).
The nearest schools are S t Oswalds VC School, Sageston CP School, Ysgol Greenhill School, Ysgol Glan y Môr, Ysgol y Preseli and Ysgol Gyfun Gymraeg Bro Myrddin.