Sergey Viktorovich Chemezov (Russian: Серге́й Ви́кторович Чемезов, b. August 20, 1952, Irkutsk Oblast, Soviet Union) is a former KGB agent and later Russian businessman and official.
In 1983–1988 he worked as an undercover KGB agent in an obscure company in Dresden, East Germany, where his neighbor was KGB officer Vladimir Putin. In 1996–1999 he served as the Chief of the External Economic Relations Department of the Russian Presidential Property Management Directorate. From September 13, 1999, to November 5, 2000, he was the Director General of Promexport. On November 5, 2000, as Promexport and Rosvooruzhenie were merged into Rosoboronexport, he became a First Deputy Director General of it under Andrey Belyaninov. In December 2001 he became a member of the board of directors of the Sukhoi Corporation. He was also a member of the board of directors of Almaz. Since June 2002, as Almaz Scientific Industrial Corporation and Antey Corporation merged into Almaz-Antey in June 2002, he has been a member of the board of directors of the latter. Since April 28, 2004, he has been the Director General of Rosoboronexport. In November 2007 he became Director-General of Russian Technologies State Corporation, the sprawling state holding company that owns hundreds of Russian state companies including many of its leading and most important industrial and military-industrial companies.