Two vessels of the Royal Canadian Navy have been named HMCS Rainbow, after the rainbow.
, an protected cruiser operated by the Royal Navy from 1893 to 1909 as HMS Rainbow, transferred to Canada in 1910, and operated until 1920 , a operated by the United States Navy from 1944 to 1968 as , sold to Canada in 1968, and operated until 1974
See also , nine ships of the Royal Navy, including the first HMCS Rainbow , a distilling ship and submarine tender of the United States Navy