Plouguenast-Langast (French pronunciation: [pluɡna lɑ̃ɡa]; Breton: Plougonwaz-Lanwal) is a commune in the Côtes-d'Armor department of Brittany in northwestern France.

It was established on 1 January 2019 by merger of the former communes of Plouguenast (the seat) and Langast.

The average annual rainfall is 966.8 mm (38.06 in) with January as the wettest month.

The temperatures are highest on average in August, at around 17.5 °C (63.5 °F), and lowest in January, at around 5.3 °C (41.5 °F).

This Côtes-d'Armor geographical article is a stub.