Locmariaquer (French pronunciation: [lɔkmaʁjakɛʁ]; Breton: Lokmaria-Kaer) is a commune in the Morbihan department in Brittany in north-western France.

It lies 8.5 mi (13.7 km) south of Auray by road.

This coat of arms was created 30 years ago by the local artist Jean-Baptiste Corlobé. The arms portray:

All are surmounted by a baronial crown (Locmariaquer was part of the former barony of Kaër). It bears the Breton language motto: "Kaër e mem bro" which can be interpreted in two ways: "Kaër is my country" or "my country is beautiful" (the phrase originated with JM François Jacob in 1933).

From the Breton loc which means hermitage (cf.: Locminé), Maria and kaer which means nice or more likely from the Old Breton caer (Modern Breton, ker) which means fortified place, city.

The municipality of Locmariaquer is located at the western tip of the Gulf of Morbihan in Brittany and has many beaches facing the Atlantic Ocean and the bay Quiberon.

This small town contains the Locmariaquer megaliths, some of the most significant neolithic remains in Europe, including the Broken Menhir of Er Grah, the largest known single block of stone to have been transported and erected by Neolithic man. It is beside the Table des Marchands, a dolmen with notable carvings.

In the nineteenth century it became the home of the writer Zénaïde Fleuriot, who idealised it in her novels.