Blackfish is a common name for several species of fish.
Blackfish may also refer to:
- Blackfish, a catch-all slang term for small, dark-colored toothed whales such as the pygmy sperm whale, the false killer whale, and the short-finned pilot whale
- Blackfish (film), a 2013 documentary focusing on the orca Tilikum held by SeaWorld
- The Black Fish, the former name of FishAct, a marine conservation organization
- USS Blackfish (SS-221), a United States Navy submarine, named for the blackfish, any one of several small, toothed whales
- Blakfish, an English math rock band that disbanded in 2010
- Blackfish (Shawnee leader)
- Brynden Tully, a character in George R.R. Martin's A Song of Ice and Fire series
- Blackfish Publishing, a British magazine publisher
- Blackfish Lake Ferry Site in Arkansas