Saint-Michel-en-Grève (French pronunciation: [sɛ̃ miʃɛl ɑ̃ ɡʁɛv]; Breton: Lokmikael-an-Traezh) is a commune in the Côtes-d'Armor department of Brittany in northwestern France.

In 2009 huge quantities of sea lettuce seaweed (Ulva lactuca) washed up on the beach at Saint Michel.

Poisonous gases resulting from its decomposition caused the death of a horse[3] and may have been a factor in the earlier death of a cleanup crew truck driver.

[4] Inhabitants of Saint-Michel-en-Grève are called michelois in French.

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