Several British and Canadian warships have been named Rainbow, after the common meteorological phenomenon.
- HMS Rainbow, a ship that took part in the Battle of Gravelines against the Spanish Armada.
- HMS Rainbow, a 44-gun frigate commanded by Henry Trollope during the American Revolution.
- In 1828, HMS Rainbow carried Admiral Henry John Rous on an exploration of northern New South Wales and named Stradbroke Island, off Queensland, Australia.
- HMS Rainbow (1891) was an Apollo-second class protected cruiser of the British Royal Navy that became the first Royal Canadian Navy ship when it was re-commissioned as HMCS Rainbow in 1910.
- HMS Rainbow was a submarine that served in World War II.
- USS Argonaut (SS-475) was renamed HMCS Rainbow and served in the Royal Canadian Navy from 1968 until 1974.


