Mehmet Ali Ağca (born January 9, 1958) is a Turkish right-wing militant who shot Pope John Paul II in Saint Peter's Square on May 13, 1981, in an assassination attempt. Following the shooting, John Paul asked people to, "...pray for my brother (Agca), whom I have sincerely forgiven." In 1983, John Paul and his would be assassin Agca met privately at the Italian prison where Agca was being held. What was said at this meeting remains secret to this day.

As a youth Agca became a petty criminal and a member of street gangs in his home town. He later became a smuggler in the lucrative trade between Turkey and Bulgaria. He then went to Syria where he received two months of training in weaponry and terrorist tactics. He claims this was paid for by the Bulgarian government. After this training he went to work for the far-right Turkish Grey Wolves, who the Bulgarians felt were a usefully destabilizing force in Turkey. Agca describes himself as a mercenary of no political orientation who was willing to do anything for enough money. In 1979, under orders from the Grey Wolves, he killed the left-wing newspaper editor Abdi İpekçi in Istanbul. He was caught due to an informant and was sentenced to life in prison. He soon escaped, with the help of the Wolves.

Agca fled to Bulgaria. There in Sofia he states that he was approached by the Bulgarian Secret Service , who offered him three million German Mark s to assassinate the Pope. It is presumed that the Bulgarians were instructed by the KGB to assassinate the Pope because of his support of Poland's Solidarity movement. However many feel Agca's story is dubious at best. No definite motive has been established.

Beginning in August 1980 Agca began crises crossing the Mediterranean region, changing passports and identities, likely to hide his point of origin in Sofia. He entered Rome on May 10, 1981 coming by train from Milan.

In Rome he claimed that he met up with three accomplices, one fellow Turk and two Bulgarians. According to Agca the entire operation was commanded by Zilo Vassilev the Bulgarian military attaché in Rome.

The plan was for Agca, and a back-up gunman Oral Celik , to fire from St. Peter's Square and then detonate a panic bomb to create chaos and allow the group to escape to the Bulgarian embassy. On May 13 they sat in the square writing postcards waiting for the Pope to arrive. When he passed Agca fired two shots at the Pope, however he was grabbed by the members of the crowd and prevented from continuing to fire or escape. Celik panicked and did not set off his bomb, or fire at the Pope, instead disappearing into the crowd.

Originally Agca claimed to be a member of the Popular Front for the Liberation of Palestine, but they denied any ties to him.

Soon after Sergei Antonov , one of the Bulgarians was arrested based on Agca's testimony. After a three year trial he was found not-guilty for want of evidence. Agca's testimony proved to be often contradictory and occasionally descended into insane ranting, including claims of being Jesus Christ. The Bulgarians have always insisted they were innocent and argued that Agca story an anti-communist plant placed by the far-right Grey Wolves, the Italian secret service, and the CIA.

Agca was sentenced to life imprisonment in Italy, but was pardoned by president Carlo Azeglio Ciampi in June 2000. Agca returned to Turkey, where he was imprisoned for the murder of Abdi İpekçi.

Agca is quoted as saying "To me [the pope] was the incarnation of all that is capitalism."