666 may refer to multiple artists:

1. 666 was a German DJ act, formed by Thomas Detert and Mike Griesheimer in 1997. They produced a mix of electronic music and often included lyrics in Spanish and English. The act disbanded in 2005.

2. A heavy/speed metal band from Caseros, Buenos Aires, Argentina, which released a demo in 1986.

3. A thrash/black metal band from Czechia.

4. A black metal band from Hungary.

5. A groove/thrash metal/hard rock band from Japan.

6. A crossover thrash band from Japan, also known as Triangle Six of Death.

7. A black/heavy metal band from Norway. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.