Llanychaer (English: church on the Aer, a tributary of the River Gwaun) is a small rural village and parish in the community of Cwm Gwaun, north Pembrokeshire, Wales.

Early in the 19th century the population was 176 and only half the land in the parish was enclosed.

[4] There are two bridges crossing the Gwaun in the north of the parish: at Cilrhedyn and Llanychaer.

[6] Llanychaer (as Llanachaier) appears on a 1578 parish map of Pembrokeshire.

The present church was completely rebuilt on earlier foundations about 1876.