Hillion (French pronunciation: [iljɔ̃] ⓘ; Breton: Helion; Gallo: Hilion) is a commune in the Côtes-d'Armor department of Brittany in northwestern France.

Mussel farming is an important activity since 10% of French mussels, about 3 000 to 4 000 tons are produced in Hillion[citation needed].

Each year, the festival "La fete de la moule" (mussels festival) is held in August in the mussels farm.

Inhabitants of Hillion are called hillionnais in French.

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