Adolf Georgievich Tolkachev (Russian: Адольф Георгиевич Толкачёв; 6 January 1927 in Aktyubinsk, Kazakhstan – 24 September 1986) was a Soviet electronic engineer who provided key documents to the American Central Intelligence Agency (CIA) between 1979 and 1985. Working at the Soviet radar design bureau Phazotron as one of the chief designers, Tolkachev gave the CIA complete detailed information about such projects as the R-23, R-24, R-33, R-27, and R-60, S-300; fighter-interceptor aircraft radars used on the MiG-29, MiG-31, and Su-27; and other avionics. He was executed as a spy in 1986.