N99

N99 or N-99 may refer to:
 * Brandywine Airport, in West Goshen Township, Pennsylvania, United States; formerly assigned FAA LID N99
 * HMS Upholder (N99), a submarine of the Royal Navy
 * N99 motorway (Netherlands)
 * Nebraska Highway 99, in the United States
 * NIOSH N99, a rating for respirators and surgical masks
 * NR-N99 tank droid, a fictional vehicle in the Star Wars universe