Grown Below is a post-metal band from Mortsel near Antwerp, formed in 2011 from the remains of a band called Timer, influenced by Cult of Luna, Isis, and Tool. They signed to Slow Burn Records and released The Long Now in 2011, followed by The Other Sight, pursuing a dense, evolved post-metal sound.

Grrrmba is a blackened doom/sludge metal band from Budapest, Hungary, formed in 2016 by members of Jack, Long Pig, My First Knife, and other Hungarian bands. Their releases include Imminent, Coalescence, Embodiment, and a split with Boru.

Grub Nap is a sludge metal/hardcore band from Leeds, formed in 2023. They deliver crushing sludge with hardcore intensity from the West Yorkshire city.

Gruel is a sludge/doom metal band from Bradford in West Yorkshire, formed in 2017. Their name — evoking thin, unappetizing gruel — contrasts with the thick, heavy sludge doom they deliver.

Grunter is a sludge metal band from Ancona on the Adriatic coast, formed in 2014. They deliver heavy sludge from the Marche regional capital.

Guantanamo Party Program is a five-piece sludge metal and post-hardcore band from Wrocław, Poland, active since 2010 with four numbered albums documenting their evolution. The project merges the crushing weight of sludge with post-hardcore's dynamic intensity.

Gud is a sludge/doom metal band from Drammen, formed in 2025. Their name — Norwegian for 'God' — contrasts with the crushing heaviness of their sludge doom.

Gufonero is a sludge metal/post-hardcore band from Trento in Trentino, formed in 2016. Their name — Italian for 'dark owl' — captures the nocturnal, heavy character of their music from the Alpine city.

Gunmouth is a sludge/stoner/doom metal band from Hamburg, Germany, formed in 2021, dealing in low-end-heavy, distortion-drenched slow jams. The band channels the heaviest, grittiest side of Hamburg's rock and metal underground.