Eighteen ships of the Royal Navy have been named HMS Lion, after the lion, an animal traditionally associated with courage, and also used in several heraldric motifs representing England, Scotland and the British Monarchy. Another ship was planned but never completed:
- Lion was a 36-gun ship of the Royal Scottish Navy captured in 1511 and sold in 1513.
- Lion was a 50-gun ship built in 1536 and on the navy list until 1559.
- Lion was a Scottish ship captured in 1547 and later lost off Harwich.
- Lion was a 40-gun ship, also known as Golden Lion. She was rebuilt four times, in 1582, 1609, 1640 and 1658. After her 1609 rebuild she was renamed Red Lion, but this was reverted to Lion after the 1640 rebuild. She was sold in 1698.
- HMS Lion was a 6-gun ketch, also known as Young Lion. She was captured from the Dutch in 1665, sold in 1667, repurchased in 1668 and sunk as a foundation at Sheerness in 1673.
- HMS Lion was a fifth rate captured from the Algerians in 1683 and sold the same year.
- HMS Lion was a 4-gun hoy purchased in 1702. She was captured by the French in 1707, but was recaptured in 1709 and rebuilt that year. She is listed in the records until 1737.
- HMS Lion was a 60-gun third rate launched in 1709, rebuilt in 1738 and sold in 1765.
- HMS Lion was a transport launched in 1753, hulked in 1775, and sold in 1786.
- HMS Lion was a cutter purchased in 1763 and sold in 1771.
- HMS Lion was a discovery vessel in service from 1774 to 1785.
- HMS Lion was a 64-gun third rate launched in 1777. She was used as a sheer hulk from 1816 and was sold for breaking up in 1837.
- HMS Lion was a schooner purchased around 1781 and sold in 1785.
- HMS Lion was a 4-gun gunvessel, originally a Dutch hoy. She was purchased in 1794 and sold in 1795.
- HMS Lion was a schooner in service from 1823 and sold in 1826.
- HMS Lion was an 80-gun second rate launched in 1847. She was converted to screw propulsion in 1859 and became a training ship after 1871. She was sold for breaking up in 1905.
- HMS Lion was a Lion-class battlecruiser launched in 1910 and sold in 1924.
- HMS Lion was to have been a Lion-class battleship. She was laid down in 1939, but work was suspended later that year, and again in 1942. The order was finally cancelled in 1945 and she was broken up on the slipway.
- HMS Lion was a Tiger-class cruiser launched in 1944 as the Minotaur class HMS Defence. She was finally completed to a revised design in 1960. She was placed in reserve in 1964 and was scrapped in 1975.