| Grand Duke Sergei Mikhailovich | |
|---|---|
 | |
| Born | 7 October 1869 Borjomi, Tiflis Governorate, Russian Empire |
| Died | 18 July 1918 (aged 48) Alapayevsk, Russian Soviet Federative Socialist Republic |
| House | Holstein-Gottorp-Romanov |
| Father | Grand Duke Michael Nikolaevich of Russia |
| Mother | Princess Cecilie of Baden |
Grand Duke Sergei Mikhailovich of Russia (Russian: Серге́й Миха́йлович; 7 October 1869 – 18 July 1918) was the fifth son and sixth child of Grand Duke Michael Nikolaievich of Russia and a first cousin of Alexander III of Russia.
He was born and raised in the Caucasus, where his father was viceroy. In 1881 the family moved to Saint Petersburg. He became a close friend of the then Tsarevich Nicholas. They grew apart upon Nicholas II's marriage and accession to the throne. Grand Duke Sergei remained a bachelor living at his father's palace in the imperial capital. He had a long affair with the famous ballerina Mathilde Kschessinska, who had previously been the mistress of Nicholas II. She was also later involved with Grand Duke Andrei Vladimorovich. Sergei recognized Mathilde's son as his own and remained their protector until his death.
Following family tradition, Grand Duke Sergei pursued a military career. He served as General Inspector of the Artillery with the rank of Adjutant General. During World War I he was chief of the artillery department, a position he was forced to resign amid controversy. He was then appointed Field Inspector General of Artillery at Stavka. After the fall of the monarchy, he remained in the former Imperial capital keeping a low profile. With the ascension of the Bolshevists to power, he was sent to internal Russian exile.
He was murdered by the Bolsheviks along with several other Romanov relatives and his personal secretary at Alapayevsk on 18 July 1918, one day after the murder of Tsar Nicholas II and his immediate family at Yekaterinburg.