Llanellen (Welsh: Llanelen) is a village in Monmouthshire, south-east Wales, United Kingdom. It is located three miles (4.8 km) south of Abergavenny.
The population was 506 in 2011.
The church of St Helen possibly dates back to the 13th century, though the church was largely re-built in Perpendicular style in the mid-19th century by architect John Prichard. In the churchyard is the grave of Sir Thomas Phillips, Mayor of Newport at the time of the Newport Rising in 1839, and a prominent defender of Welsh language and education, who lived in nearby Llanellen House.