Landerneau (Landerne in Breton) is a commune in the Finistère department of Brittany in north-western France.

It lies at the mouth of the Elorn River which divides the Breton provinces of Cornouaille and Léon, 20 km (12 mi) east of Brest. The name means "(religious) enclosure of St Ténénan (Welsh:Tyrnog)": allegedly a Welshman who also had llans in the Vale of Clwyd in North Wales and in Somerset, and who moved to Brittany in the 7th century. It was an important centre of the flax and linen industries in the 16th and 17th centuries. Today it is the main agricultural market in northwest Brittany.