Fethullah Gülen (born in 1941) is a Turkish preacher, former imam, and writer. He is the founder of the Gülen movement (known as Hizmet meaning service in Turkish). He currently lives in self-imposed exile in the United States, residing in Saylorsburg, Pennsylvania.

Gülen teaches an Anatolian (sort of Hanafi) version of Islam, deriving from Sunni Muslim scholar Said Nursî's teachings. Gülen has stated that he believes in science, interfaith dialogue among the People of the Book, and multi-party democracy. He has initiated such dialogue with the Vatican and some Jewish organizations.

Gülen has been described in the English-language media as an imam "who promotes a tolerant Islam which emphasises altruism, hard work and education" and as "one of the world's most important Muslim figures."