Tréogat (French pronunciation: [tʁeɔɡat]; Breton: Trêgad) is a commune in the Finistère department of Brittany in north-western France.

Forming part of the boundary between Tréogat and the commune of Tréguennec is the Étang de Trunvel or Trunvel pond or lake; a coastal marsh covering 264 hectares (1 sq mi) and listed as a type 1 Zone naturelle d'intérêt écologique, faunistique et floristique (ZNIEFF).

The invasive water primrose, Ludwigia uruguaynensis, viewed as a threat to native aquatic vegetation has been found here and uprooted.

At Penhors stands a megalith in the form of a 3.6 m (12 ft) tall fluted, granite protohistoric stele originally from Saint-Mélon chapel in Tréogat.

[5][6] Two 16th-century stone crosses stand; one 2.8 m (9.2 ft) tall on the Rue de la Fontaine, close to the Church of Saint Boscat and the other at Kerguenol, 1 km south.