Henning Rudolf Adolf Karl von Holtzendorff (9 January 1853 – 7 June 1919) was a German admiral during World War I, who became famous for his December 1916 memo about unrestricted submarine warfare against the United Kingdom.

He was a recipient of Order of the Black Eagle and the Pour le Mérite with oak leaves and was one of just six Grand Admirals of the Imperial German Navy.

He served as chief of staff at the Baltic Sea Naval Station and was director of the Imperial Shipyard at Danzig, before becoming a Vice Admiral in 1904.

The belief that unrestricted submarine warfare would starve Britain and bring about its demise was predicted, with the statement that the United Kingdom will be forced to sue for peace within six months.

He was retired again after quarrels about war aims with the Oberste Heeresleitung (Supreme Army Command) in August 1918 and replaced by Admiral Reinhard Scheer.