XN may refer to:
- crossed Nicols, see Nicol prism
- the two-letter code of the Nordic Patent Institute
- the four-character prefix "xn--" used in the ASCII representation of Internationalized domain names
- a shorthand abbreviation for Christian, based on the Greek letter Chi (letter) used by early Christians
- a part of a notation indicating a nuclear reaction that is expected to produce one or more neutrons
- the Canadian artist Christian Cardell Corbet, who uses XN as an abbreviation of his name