Reino Häyhänen (Russian: ????? ????????; 14 May 1920 – 17 February 1961) was a Soviet intelligence officer of the KGB who defected from the Soviet Union to the United States in May 1957.
Häyhänen surrendered information on Soviet espionage activities that solved the Hollow Nickel Case for the FBI, and led to the arrest of his KGB partner Rudolf Abel and other Soviet spies in the United States and Canada.