Martial Allart is a progressive metal project from Reims, France, formed in 2024. The project explores progressive metal's technical and compositional possibilities.

Mask of Prospero is a progressive metal band from Athens, Greece, formed in 2018, having evolved into progressive metalcore and djent. Their creative evolution reflects an embrace of modern progressive metal's rhythmic complexity.

A post-metal and progressive metal band from Charleroi in Wallonia, Massive Therapy build dense, textured compositions that favor atmosphere and dynamic range over conventional song structures. The band have released recordings through Bandcamp, contributing to Belgium's thriving post-metal underground that has produced internationally recognized acts from the Walloon region.

Mastord is a progressive metal band from Kotka, Finland, formed in 2019. They craft intricate progressive metal compositions with technical ambition and creative depth.

Mater Thallium is a doom metal and progressive rock act from Trondheim, active since 2013. The band blends the crushing weight of doom with the exploratory spirit of progressive rock from Norway's third-largest city.

Mayfair were a progressive metal band from Frastanz in Vorarlberg, Austria, formed in 1989 and among the earliest Austrian acts to engage with the progressive metal sound emerging in the early 1990s. Their style combined hypnotic cyclical riffing reminiscent of Tool with ethnic percussive elements and European folk-tinged melodies, evolving toward avant-garde rock on later releases. The band released three albums in the 1990s and reunited in 2010, remaining active until 2022.

Mayfire is a progressive metal band from Norway, formed in 2023. They craft intricate progressive compositions with technical ambition.

A progressive doom metal act from Ajaccio on the island of Corsica, Mazzeri draws from local mythology — the Mazzeri being Corsican dream-hunters who predict death. Active since 2020, the band channels the island's unique cultural traditions into haunting, crushing doom.

Maïeutiste is a band from Saint-Étienne, France, formed in 2015, having evolved from black and doom metal into progressive black metal. Their creative arc reflects a deepening exploration of black metal's atmospheric and compositional possibilities.