Sergei Aleksandrovich Tumasyan (; born 31 January 1990) is a Russian former professional footballer who played as a midfielder.
Tumasyan made his professional debut for FC Rostov on 13 July 2010 in the Russian Cup game against FC Salyut Belgorod.
Tumasyan joined Metallurg Bekabad in Uzbekistan for the 2019 season.
He is the older brother of Aleksandr Tumasyan, younger brother of Denis Tumasyan and a son of Aleksandr Tumasyan.
Dragon Pathumwan Kanchanaburi