SM U-13^{[Note 1]} was one of the 329 submarines serving in the Imperial German Navy in World War I. U-13 was engaged in the naval warfare and took part in the First Battle of the Atlantic.

She had left Heligoland on 6 August 1914 and was not heard from again. She may have been a victim of the German defensive minefield in Heligoland Bight, or from an accident or mechanical failure.

• Gröner, Erich; Jung, Dieter; Maass, Martin (1991). German Warships 1815–1945, U-boats and Mine Warfare Vessels. Vol. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
• Kemp, Paul (1997). U-boats destroyed, German submarine losses in the World Wars. London: Arms & Armour Press. p. 9. ISBN 1-85409-321-5.

• Helgason, Guðmundur. "WWI U-boats: U 13". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 14 March 2015.