Aggressor may refer to:
- Aggressor (album), a 2003 synthpop album
- HMS Aggressor, two Royal Navy ships
- USS Aggressor, two US Navy ships
- Aggressor squadron, a US military unit acting as an opponent in wargames
- Aggressor (novel), a 2005 novel by Andy McNab
- Aggressor (horse) a Thoroughbred racehorse
- Aggressor, former name of the Estonian rock band, No-Big-Silence.