XO

XO may refer to:
* Executive officer in the military
* Executive order, an edict by a member of the executive branch of a government
* XO, the now-deprecated abbreviation for crystal oscillators on electrical schematic diagrams
* XO, a grade of cognac, meaning "extra old"
* XO, the IATA code for Spain's LTE International Airways
* "XO" (album) by singer-songwriter Elliott Smith
* XO Communications, a telecom company
* XO sauce, a spicy seafood sauce
* XO Telescope and its related exo-planet survey
* "XO", a song on Fall Out Boy's third studio album, From Under The Cork Tree

ee also

* Chi Omega ("ΧΩ"), a National Panhellenic Conference women's fraternity
* Eastern Orthodoxy Christianity (from the Greek: Χριστιανός Ορθόδοξος, "Xristianos Orthodoksos")
* Hugs and Kisses, sometimes written as a sequence of XOs
* OLPC XO-1 laptop, produced by the One Laptop per Child association
* Tic-tac-toe, a game using X's and O's
* Turner syndrome, a disorder in which all or part of an X chromosome is absent
* X0 sex-determination system, as found in insects
* XOXO, an XML microformat