USN (disambiguation)

The USN or United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States.

USN may also refer to:
 * University School of Nashville
 * IATA Code for Ulsan Airport in Ulsan, South Korea
 * Ubiquitous Sensor Network
 * USN (Update Sequence Number) Journal, a part of the NTFS file system
 * United States dollar (next day) (funds code)
 * Universal Space Network, a company providing space communication services