Zeibeks or sometimes Zeybeks were irregular militia and guerilla fighters living in the Aegean Region of the Ottoman Empire from late 17th to early 20th centuries, generally of Turkmen and Yörük origins.
Before the establishment of the Republic of Turkey, large concentrations of Zeibeks could be found in western Anatolia, particularly in Isparta, Burdur, Afyon, Kütahya, Uşak, Denizli, Aydın, İzmir, Manisa, Muğla, Antalya, and the Balıkesir area.
They acted as protectors of village people against landlords, bandits and tax collectors. A leader of a Zeibek gang was called Efe and his soldiers were known as either Zeibeks or Kızan. Kızan was generally used for newly recruited or inexperienced Zeibeks. There was generally a tribe democracy in group. Decisions was taken in a democratic way, after the decision was taken Efe has an uncontroversial authority. They followed definite rituals for all actions; for example, the promotion of a kızan to zeybek was very similar to Ahi rituals.
Zeybeks had a special dance in which performers simulated hawks. Romantic songs about their bravery are still popular in Turkish folk music. The yatagan sword was their primary weapon, but most of them carried firearms as well.
The Zeibeks fought against the Greek invasion of Western Anatolia during the Greco-Turkish War of 1919-1922. Their guerrilla warfare gave time for Turkish resistance to form a defense. After the formation of a Turkish national army, most of them joined and continued their resistance.