Crystal Castles was a Canadian electronic music group formed in 2006 in Toronto, Ontario, by songwriter-producer Ethan Kath and singer-songwriter Alice Glass. It was known for their chaotic live shows and lo-fi melancholic homemade productions. They released many limited vinyl singles between 2006 and 2007 before releasing four studio albums between 2008 and 2016.

The band's origins trace back to an unusual collaboration. Ethan Kath met Alice Glass in Toronto, Ontario, when she was in the 10th grade and he was 10 years her senior. A couple of years later, Kath asked Glass to record vocals over tracks he had been working on since 2003. The sessions resulted in the track Alice Practice, which was shelved for six months. The duo's stage name has a whimsical origin: the name Crystal Castles was pulled from a line in the cartoon She-Ra: Princess of Power: The fate of the world is safe in Crystal Castles.

Crystal Castles' music was characterized by its abrasive, experimental approach to electronic music. Their sound was described by reviewer Jack Shankly as ferocious, asphyxiating sheets of warped two-dimensional Gameboy glitches and bruising drum bombast that pierces your skull with their sheer shrill force, burrowing deep into the brain like a fever. This distinctive aesthetic helped establish them as pioneers in the electroclash and chiptune scenes.

However, the band's story took a dark turn. Glass announced her departure from the band in October 2014, citing personal and professional reasons, and was soon replaced by Edith Frances. Three years later, during the band's 2017 tour, Glass accused Kath of sexual misconduct during her time in Crystal Castles, causing the remaining tour dates to be cancelled. Crystal Castles has since been inactive, having provided no updates on new material or performances after Glass's allegations.