Le Quiou (; ) is a commune in the Côtes-d'Armor department of Brittany in northwestern France.
Le Quiou has an oceanic climate (Köppen climate classification Cfb). The average annual temperature in Le Quiou is . The average annual rainfall is with November as the wettest month. The temperatures are highest on average in July and August, at around , and lowest in January, at around . The highest temperature ever recorded in Le Quiou was on 5 August 2003; the coldest temperature ever recorded was on 25 February 1986.
The inhabitants of Le Quiou are known in French as quiousiens.