HMY Conqueror II was an iron-hulled steam yacht that was launched in Scotland in 1889 as Conqueror. She belonged to Frederick William Vanderbilt from 1891, and then to William Montagu, 9th Duke of Manchester from 1911. In the First World War the Admiralty requisitioned her as an armed yacht. In 1915, she was commissioned into the Royal Navy as HMY Conqueror II. The "II" was added to avoid confusion with the dreadnought battleship HMS Conqueror. A German U-boat sank the yacht in 1916, killing 17 of her crew.