Elizabeth Terrill Bentley (January 1, 1908 – December 3, 1963) was an American spy and member of the Communist Party USA (CPUSA). She served the Soviet Union from 1938 to 1945 until she defected from the Communist Party and Soviet intelligence by contacting the Federal Bureau of Investigation (FBI) and admitting her own activities.

She became widely known after testifying in a number of trials and before the House Un-American Activities Committee (HUAC). In 1952, Bentley became a US informant and was paid by the FBI for her participation in investigations and frequent appearances before Congressional committees. She exposed two spy networks, ultimately naming more than 80 Americans who she said had engaged in espionage.