HMS Jervis Bay was a British liner later converted into an armed merchant cruiser, pennant F40. She was launched in 1922, and sunk in battle on 5 November 1940 by the German heavy cruiser Admiral Scheer in an action which earned her captain the Victoria Cross.

An armed merchantman is a merchant ship equipped with guns, usually for defensive purposes, either by design or after the fact. In the days of sail, piracy and privateers, many merchantmen would be routinely armed, especially those engaging in long distance and high value trade.