Arzon (French pronunciation: [aʁzɔ̃]) or Arzhon-Rewiz in Breton (Breton pronunciation: [aʁxɔ̃n rewis]) is a commune located at the extremity of the Rhuys peninsula in the Morbihan department in the Brittany region in northwestern France.

Arzon is said to be the French village with the longest coastal area in France (see map). Arzon marks the east entrance to the Gulf of Morbihan.

There are two seaside resorts in the commune:

Several hamlets are located on the territory of the commune: Monteno, Kerners, Béninze, Tumiac, Kerjouanno.

Arzon is a popular summer resort. In winter, fall and spring, only two "gendarmes" (French military police) work in Arzon, but in the summer there are far more to cope with the influx of tourists.

Inhabitants of Arzon are called Arzonais in French.

Arzon is twinned with Lahinch, Ireland.