Glenn Michael Souther (January 30, 1957 – June 22, 1989), also known as Mikhail Yevgenyevich Orlov, was an American sailor who became a Soviet intelligence officer after defecting to the Eastern Bloc in 1986.

In 1975, Souther graduated from high school in Cumberland, Maine, and briefly attended university before enlisting in the United States Navy where he was trained as a photographer.

Souther served on the USS Nimitz from July 1976 to November 1978, and was stationed with the United States Sixth Fleet in Italy from April 1979 to 1982, where he married an Italian woman.

Simultaneously, Souther worked as a reservist at the Atlantic Fleet intelligence center in Norfolk, Virginia, where he was assigned to a laboratory processing satellite-reconnaissance photos, and also may have been privy to sensitive communications intercepts.

Initially, Soviet counterintelligence units were suspicious of Souther's defection and feared that he was a double agent for the CIA, but he was cleared shortly afterwards.

Souther was well received by the Soviet authorities, gifting him an apartment in Moscow and a dacha on the outskirts of the city, and promoting him to the rank of major in the KGB – one of few foreign spies to be commissioned as an officer in the agency.

Souther met and befriended other foreign Soviet intelligence agents that had defected including Kim Philby and George Blake.

In mid-1988, in another interview, Souther made several statements praising his new living conditions in the Soviet Union and optimistic about the country's future.

In reality, Souther was impressed by the Soviet Union's free education and health care, well-developed public transport, and the social security system, but found much of the country had failed to live up to his expectations.

In August 1988, Souther wrote a diary entry about perestroika, the restructuring of the Soviet political and economic system occurring at the time, where he was highly skeptical and pessimistic of the reforms.