Muriaux is a municipality in the district of Franches-Montagnes in the Canton of Jura in Switzerland . On 1 January 2009, the formerly independent municipality of Le Peuchapatte merged into the municipality of Muriaux.

Muriaux is first mentioned in 1301 as Murival. The municipality was formerly known by its German name Spiegelberg, however, that name is no longer used.

Muriaux has an area of 16.88 km2 (6.52 sq mi). Of this area, 10.22 km2 (3.95 sq mi) or 60.5% is used for agricultural purposes, while 6.1 km2 (2.4 sq mi) or 36.1% is forested.