People who are commonly referred to solely by their given name Cleo include:

• Cleo Higgins, of the vocal group Cleopatra.
• Cleo Rocos, a British comedian.
• Miss Cleo, a self-proclaimed psychic.

In entertainment, things named Cleo include:

• Carry On Cleo, a 1963 film.
• "Cleo Babbitt", a fictional character in the U.S. soap opera As the World Turns.
• "Cleo Bellows" was a main character in the OPB TV show MythQuest.
• CLEO (group), a Korean pop girl-group.
• Cleo (magazine), a women's magazine.
• Cleo (TV series), a Swedish comedy TV series broadcast in two seasons during 2002 and 2003.
• "Cleo", a song by Built to Spill from their 1994 album There's Nothing Wrong with Love.
• Cleo (Disney), an animated goldfish character created by The Walt Disney Company, who first appeared in the movie Pinocchio.
• "Cleo", a purple poodle in the animated children's program on OPB Clifford The Big Red Dog.
• "Cleo", the mother lion in the OPB children's TV program Between the Lions.
• Cleo (Clone High), a fictional clone of Queen Cleopatra of Egypt in the American TV series Clone High.
• Cleo was also the name of one of The Catillac Cats, an animated TV series

Other uses of Cleo include:

• "CLEO" (Clear Language for Expressing Orders), the programming language for the LEO computer.
• "CLEO" Conference on Lasers and Electro-Optics.
• CLEO (particle detector), the name of a particle detector operated by a collaboration of physicists at Cornell University.
• CLEO (router), a satellite payload extending the Internet into space.
• Hurricane Cleo, which hit the Caribbean and Florida in 1964.