The Tavy is a river on Dartmoor, Devon, England. The name derives from the Brythonic root "Taff", the original meaning of which has now been lost. It has given its name to the town of Tavistock and the villages of Mary Tavy and Peter Tavy. It is a tributary of the River Tamar and has as its own tributaries:

• Collybrooke
• River Burn
• River Wallabrooke
• River Lumburn
• River Walkham