Mark 23

The U.S. Navy designation Mark 23 may refer to:

• Heckler & Koch Mark 23, a .45ACP-caliber handgun
• Mark 23 machine gun, a configuration of the Stoner 63 weapons system used by US Navy SEALs.
• Mark 23 Pistol and Suppressor Kit, a Vietnam War-era kit issued to US Navy SEALs, containing a Mark 22 pistol and a Mark 3 noise suppressor.
• Mark 23 torpedo, a submarine-launched anti-ship torpedo used in World War II