Sergey Shiryayev (Russian: Серге́й Ширя́ев, born February 8, 1983) is a Russian cross country skier who has been competing since 2002. His best finish at the FIS Nordic World Ski Championships was 11th in the 15 km event (9.3 miles) at the 2007 event in Sapporo, but that result was declared null and void upon announcing Shiryayev's disqualification for doping on EPO at the last day of the championships on March 4, 2007. His case was heard at the FIS Council meeting in Portorož, Slovenia in May 2007, resulting in a two year suspension from the sport. Two other coaches also received sanctions from the Russian ski federation.
Shiryayev's best World Cup finish was third in a 30 km mixed pursuit event (18.6 miles) in Russia in January 2010.
At the 2010 Winter Olympics, he finished 31st in the 15 km event while not finishing the 50 km event (31.1 miles).