Abdullah Öcalan ( OH-jə-lahn; Turkish: [œdʒaɫan]; born 4 April 1948), also known as Apo (short for Abdullah in Turkish; Kurdish for "uncle"), is a political prisoner and founding member of the militant Kurdistan Workers' Party (PKK).

Öcalan was based in Syria from 1979 to 1998. He helped found the PKK in 1978, and led it into the Kurdish–Turkish conflict in 1984. For most of his leadership, he was based in Syria, which provided sanctuary to the PKK until the late 1990s.

After being forced to leave Syria, Öcalan was abducted in Nairobi in 1999 by the Turkish National Intelligence Agency (MIT) (with assistance of the USA) and taken to Turkey, where after a trial he was sentenced to death under Article 125 of the Turkish Penal Code, which concerns the formation of armed organizations. The sentence was commuted to aggravated life imprisonment when Turkey abolished the death penalty. From 1999 until 2009, he was the sole prisoner in İmralı prison in the Sea of Marmara, where he is still held.

Öcalan has advocated a political solution to the conflict since the 1993 Kurdistan Workers' Party ceasefire. Öcalan's prison regime has oscillated between long periods of isolation during which he is allowed no contact with the outside world, and periods when he is permitted visits. He was also involved in negotiations with the Turkish government that led to a temporary Kurdish–Turkish peace process in 2013.

From prison, Öcalan has published several books. Jineology, also known as the science of women, is a form of feminism advocated by Öcalan and subsequently a fundamental tenet of the Kurdistan Communities Union (KCK). Öcalan's philosophy of democratic confederalism is applied in the Autonomous Administration of North and East Syria (AANES), an autonomous polity formed in Syria in 2012.