Llandrillo (or, in full, Llandrillo yn Edeirnion) is a small village and community in the Edeirnion area of Denbighshire in Wales, between Bala, and Corwen on the B4401 road. It was historically in the county of Merionethshire, and has a population of 580.
It is named after Saint Trillo who came from Brittany with other missionaries and who founded Llandrillo church on a mound next to the Ceidiog stream close to its confluence with the River Dee.
An electoral ward in the same name exists. This ward stretches north with a total population of 1,122.