Ernst August Anton Hermann Otto von Lauenstein (1 February 1857 – 3 October 1916) was a Prussian Generalleutnant who served during World War I.

[2] On 24 April 1904 he was sent to Russia as Prussian military envoy with the Russian Army in Manchuria.

This assessment helped Schlieffen to conclude that Russia would not be able to counterattack Prussian forces.

He returned to Germany later in the same year and became Chief of Staff of the VI Corps, commanded by Karl von Pritzelwitz.

[1][2] During World War I he first was the Chief of Staff of the 2nd Army, which played a big role in the Schlieffen Plan.

In 1915 he simultaneously commanded the Army Group Lauenstein, which consisted of 78th Reserve Division, the 6th Reserve Division, Manred von Richthofen's cavalry command and a Landwehr detachment.