Zara Yacob, b. 1592. Leading thinker of the Ethiopian Enlightenment who emphasized the importance of clear thinking. His name is variously spelled in the Roman alphabet; some common variations are Zara Yaqob, Zara Yaquob and Zera Yakob.

Zeno of Citium (333 - 264 B.C.), the founder of stoicism.

Zeno of Elea, born c. 488 BCE was a disciple of Parmenides. He is mostly known for his paradoxes of motion, e.g., Achilles and the Tortoise.

Zhu Xi (Chu Hsi, Hsu Chi), 1130-1200. Confucian scholar and founder of the Neo-Confucian movement. Opposed Buddhist influences in Chinese thought, and based his own philosophy on a return to the Confucian canon. An intimate knowledge of his writings was required to pass state examinations in China and Korea until modern times.

Slavoj Zizek, b. 1949. Slovenian philosopher primarily known as a critic of modern culture and member of the "Lacanian" school of thought. He has also been an important figure in the political development of Slovenia.

Florian Znaniecki, 1882-1958. Polish-American philosopher, sociologist, and philosopher of social science.

Xavier Zubiri, 1898-1983. Spanish philosopher best known for his work in metaphysics and the history of philosophy.

Slovenian philosopher whose work focuses on psychoanalysis and continental philosophy