Four ships of the Royal Navy have been named HMS Formidable with a fifth, the French Formidable, renamed HMS Ham after being captured and recommissioned; a sixth has been announced:
was a second rate; initially of 90 guns, later increased to 98; 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.
was an 84-gun second rate launched in 1825. She was lent as a training ship in 1869 and was sold in 1906.