Alexander Samsonov (1859 - August 29, 1914) was a Russian military leader during World War I.

He joined the Russian Army at age 18 and fought in the Russo-Turkish War, 1877-78. After the war Samsonov attended the Nikolaevsky Military Academy in St. Petersburg. He commanded a cavalry unit during the Boxer Rebellion (1900) and the Russo-Japanese War (1904-05).

Through these conflicts Samsonov gained a reputation as an energetic and resourceful leader, but some were critical of his strategic abilities. After the Battle of Mukden in 1905 he accused General Paul von Rennenkampf of failing to assist him during the fighting and the two men came to blows. After the Russo-Japanese War Samsonov was made Chief-of-Staff of Warsaw Military District and later as military leader in Turkestan.

With the start of World War I, Samsonov was given command of the Russian Second Army for the invasion of East Prussia. He advanced slowly into the south western corner of East Prussia intending to link up with General Rennenkampf advancing from the north east section. However, lack of communication between the two would hinder coordination.

General (later Field Marshal) Paul von Hindenburg and General Erich Ludendorff, whom were sent to replace General Maximilian von Prittwitz , engaged Samsonov's advancing forces. They made contact on August 22 and for six days the Russians, possessing numerical superiority, had some successes. However, by August 29 Samsonov's Second Army was surrounded at Tannenberg.

General Samsonov attempted to retreat, but with his army now trapped in a German encirclement, most of his troops were killed or captured. Only 10,000 of the 150,000 Russian soldiers managed to escape the cordon. Shocked by the disastrous outcome of the battle and unable to face reporting the scale of the disaster to Tsar Nicholas II, Samsonov committed suicide by a shot to the head on August 29, 1914.