Blackwater can refer to:
- Blackwater Rush - the river that flows into Blackwater Bay in the Crownlands.
- Blackwater Bay - the bay of the Narrow Sea that the Blackwater Rush empties into; King's Landing is located on the north bank of the river's mouth where it enters the bay.
- Battle of the Blackwater - Stannis Baratheon's assault on King's Landing, launched from his fleet in Blackwater Bay which landed at the mouth of the Blackwater Rush to attack the city.
- "Blackwater" - The ninth episode of Season 2, featuring the Battle of the Blackwater.