Sergey Smiryagin (Russian: Серге́й Смирягин; 27 October 1963 – 11 July 2020) was a Russian freestyle swimmer. He competed at the 1980 Summer Olympics in the 100 m freestyle, but failed to reach the final. After the Olympics he won three European titles and three silver medals at the world championships, as well as a gold medal at the 1983 Summer Universiade. He missed the 1984 Summer Olympics due to their boycott by the Soviet Union and competed in the Friendship Games instead, winning three gold medals.