Matthias Warnig (born 26 July 1955) is a former East German Stasi officer and a Russia-based businessman who has worked closely with Vladimir Putin.

[5][6] In 1974 Warnig started his career at the Stasi, the secret police of communist East Germany, and entered its foreign intelligence (HVA) on April 1, 1975.

[11][b] He allegedly worked as the Deputy Chief of the Science and Technology Sector (STS) (German: Sektors Wissenschaft und Technik (SWT)), which is often referred to as industrial espionage or economic espionage (German: Wirtschaftsspionage) under Horst Vogel [de] in A XIII [de] of the HVA, headed the work group Department 5 (Referat 5 / SWT) and attempted to obtain information from the West about materials technology, chemistry, electronics, physics and nuclear power.

[7] Warnig, however, has denied this by saying that they met for the first time in 1991, when Putin was the head of the Committee for External Relations of the Saint Petersburg Mayor's Office.

[29] Warnig was a resident of Düsseldorf from 1986 living in an apartment in the district of Bilk as a trade representative of the GDR.

[44] During violent gang wars involving the Tambov Gang while it was taking control of St. Petersburg's energy trade in the 1990s, Maria Vorontsova and her sister Katerina Tikhonova were sent by their father Vladimir Putin, who feared for their safety, to Germany where their legal guardian was Warnig.