Sergey Vasilyevich Fesikov (Russian: Серге́й Васильевич Фесиков, born 21 January 1989) is a Russian swimmer. He was part of the Russian 4×100 m freestyle relay teams that finished in ninth and third place at the 2008 and 2012 Olympics, respectively.
Fesikov's parents are former competitive volleyball players. In the 2000s, his father, a renown volleyball coach, received various job offers in Yaroslavl and Obninsk and moved his family there from Saint Petersburg. In 2010, Fesikov graduated from the Yaroslavl State University with a degree in social studies. In August 2013 he married Anastasia Valeryevna Zuyeva, an Olympic swimmer who also competed at the 2008 and 2012 Games.