Goo may also refer to:

• Goo (programming language), a programming language in the Lisp family
• goo (search engine), a Japanese web search engine
• Gasper goo, a North American fish
• Grey goo, a hypothetical future mass of self-replicating nanobots

In entertainment:

• Goo (Gumby character), a character on The Gumby Show
• Goo (album), by the band Sonic Youth
• Goo Goo Dolls, a North American alternative rock band
• Goo Goo Gaga, a character in the television series Foster's Home for Imaginary Friends

GOO may refer to:

• Gastric outlet obstruction, a medical condition where the outflow of the stomach is blocked
• Goole railway station, England; National Rail station code GOO
• Guardians of Order, defunct Canadian company of role-playing games
• Get Oil Out, an environmental group formed in Santa Barbara after the 1969 oil spill