Klaus Barbie (October 25, 1913 - September 25, 1991) was a German officer of the SS and the Gestapo (secret police) during the Nazi regime.

Barbie used the alias Klaus Altmann while he was hiding in Bolivia.

Barbie was born in Bad Godesberg and was educated at the Friedrich-Wilhelm Institute. He joined the SS in 1934, immediately after his graduation from the university, and became a member of the NSDAP in 1937.

In 1941, Barbie was posted to the Bureau of Jewish Affairs and sent to Amsterdam and later, in May 1942, to Lyon—there, he earned the sobriquet "Butcher of Lyon" as head of the local Gestapo. He was accused of a number of crimes, including the capture and deportation of forty-four Jewish children hidden in the village of Izieu and the torturing to death of Jean Moulin, the highest ranking member of the French Resistance ever captured. All told, the deportation of 7,500 people, 4,342 murders, and the arrest and torture of 14,311 resistance fighters were in some way attributed to his actions or commands.

From 1945 to 1955, he was protected and employed by British and then American intelligence agents because of his "police skills". In 1955, Barbie, together with his wife and children, escaped to Bolivia. He lived in La Paz under the alias Klaus Altmann. He was identified in Bolivia in 1971 by the Klarsfelds (Nazi hunters), but it was only on January 18, 1983 that a new moderate government arrested and deported him to France. He was defended by Jacques Verges and his trial started on May 11, 1987 in Lyon. On July 4 of that year, he was sentenced to life imprisonment for crimes against humanity and later died in prison of cancer.

A documentary film on Barbie's life during and after World War II is available under the title Hôtel Terminus: The Life and Times of Klaus Barbie. The film was directed by Marcel Ophuls and amounts to four and a half hours of investigative journalism; it won the Academy Award for Documentary Feature in 1989.