Kook (pronounced with a long "oo") may refer to

• Abraham Isaac Kook, Chief Rabbi in the British Mandate of Palestine, considered to be Israel's first Chief Rabbi.
• Zvi Yehuda Kook, son of the above, prominent Religious Zionist rabbi.
• Hillel Kook, nephew of Abraham Isaac Kook, prominent Revisionist Zionism activist during World War Two.
• Kook, in skateboarding, a beginner skateboarder

• Kook, in surfing, an unskilled surfer
• Kook, in Yiddish, means "look"
• A pejorative term for someone; a crank.
• net.kook, a crank found on Usenet newsgroups.
• The Kooks, a British indie band.
• Kooks, a 1971 David Bowie song.