N99 or N-99 may refer to:
*
Brandywine Airport, in West Goshen Township, Pennsylvania, United States; formerly assigned FAA LID N99
* , a submarine of the Royal Navy
*
N99 motorway (Netherlands)
*
Nebraska Highway 99
Nebraska Highway 99 is a highway in southeastern Nebraska. It has a southern terminus at the Kansas border south of Burchard and just north of Summerfield, Kansas. Its northern terminus is north of Burchard at an intersection with Nebraska ...
, in the United States
*
NIOSH N99
The NIOSH air filtration rating is the U.S. National Institute for Occupational Safety and Health (NIOSH)'s classification of filtering respirators. The ratings describe the ability of the device to protect the wearer from solid and liquid part ...
, a rating for respirators and surgical masks
*
NR-N99 tank droid, a fictional vehicle in the ''Star Wars'' universe
{{Letter-Number Combination Disambiguation