Sergey Ivanovich Muravyov-Apostol (Russian: Серге́й Ива́нович Муравьёв-Апо́стол) (9 October [O.S. 28 September] 1796 – 25 July [O.S. 13 July] 1826) was a Russian Imperial Lieutenant Colonel and one of the organizers of the Decembrist revolt.
He was one of five "Decembrists" executed for their roles in attempting to overthrow the monarchy.
Sergei was born in Saint Petersburg, the fourth son of Russian diplomat Ivan Muravyov-Apostol. His mother, Anna, was the daughter of a Serbian general, Simon Crnojević. Four of his relatives were also Decembrists: his brothers Ippolit Muravyov-Apostol and Matvey Muravyov-Apostol and cousins Nikita Muravyov and Artamon Muravyov.
Sergei spent his childhood in Hamburg and Paris, then graduated from Saint Petersburg Institute of Road Engineers before joining in the Russian Army.
He was a veteran of the Patriotic War of 1812. He took part in the Battle of Vitebsk, the Battle of Borodino, the Battle of Tarutino, the Battle of Maloyaroslavets, the Battle of Berezina, (for which he was awarded the Golden Sword for Bravery), the Battle of Leipzig, and the Battle for Paris, for which he was awarded with the Order of St. Anna, second degree.