OO or oo may refer to:
Udagamandalam (also Ootacamund ( listen )) and abbreviated as Udhagai and Ooty ( listen is a town and municipality in the Indian state of Tamil Nadu.
Oops!... I Did It Again is the second studio album by American singer Britney Spears. It was released on May 16, 2000 in the United States through Jive Records.
Oobi is an American children's television series created by Josh Selig of Little Airplane Productions.
Oophorectomy (from Greek ᾠοφόρος, ōophóros, "egg-bearing" + ἐκτομή, ektomḗ, "a cutting out of") is the surgical removal of an ovary or ovaries.
The Oort cloud (), named after the Dutch astronomer Jan Oort, sometimes called the Öpik–Oort cloud, is a theoretical cloud of predominantly icy planetesimals proposed to surround the Sun to as far as somewhere between 50,000 and 200,000 AU (0.8 and 3.2 ly).
Ooredoo (Arabic: أوريدو; formerly Qtel) is an international telecommunications company headquartered in Doha, Qatar.
Oopiri (lit. Breath) is a 2016 Indian comedy-drama film directed by Vamsi Paidipally. A remake of Olivier Nakache & Éric Toledano's French comedy-drama The Intouchables (2011), the film was produced by Prasad V.
"Oops!... I Did It Again" is a song by American singer Britney Spears, from her second album of the same name.
Oogenesis, ovogenesis, or oögenesis is the differentiation of the ovum (egg cell) into a cell competent to further development when fertilized.