Llanllwni is a village and community located in Carmarthenshire, Wales. The village lies along the A485 highway, stretching for about 2.5 mi (4.0 km), to the south-west of Llanybydder. To the south of the village lies Llanllwni Mountain. The 16th-century parish church, formerly dedicated to St. Llwni, is now dedicated to St. Luke and is a grade II* listed building.