Five ships of the Royal Navy have been named HMS Formidable.
- HMS Formidable was an 80-gun second rate captured from the French at the Battle of Quiberon Bay in 1759, and broken up in 1768.
- HMS Formidable was a 90-gun second rate launched in 1777. She fought at the Battle of Ushant and the Battle of the Saintes, was converted to a 74-gun third rate in 1813, and broken up later that year.
- HMS Formidable was an 84-gun second rate launched in 1825. She was lent as a training ship in 1869 and was sold in 1906.
- HMS Formidable was a Formidable-class predreadnought battleship launched in 1898 and torpedoed and sunk in 1915.
- HMS Formidable was an Illustrious-class aircraft carrier launched in 1939 and sold for scrap in 1953.