Llanio Methodist Sunday School Chapel was built in 1858. The Sunday school was originally started after Jac Coch, a servant at Llanio Mawr, requested the use of a barn to start a Sunday school in 1796.

A stone building with brick dressings, it was built as a long-wall chapel in the Simple Round-Headed style. There was a single, round-headed doorway to the left-hand bay, with a Y-glazed fanlight over it, and three equally spaced, tall, round-headed windows to the right of this all with simialr glazing. There is a plaque dedicated to the librarian Alun R Edwards, 1919-1986 with the inscription 'Yr oedd cell y llyfrygellyd-yn rhy gul/I'r galon aflonydd/eiffiniau oedd friniau ffydd/Y Walia hwnt I'r welydd'.

By 2011 the chapel had been converted for residential use.

RCAHMW, October 2015