Na can refer to:
- Sodium, chemical element
- The name of a tribal people of Arunachal Pradesh. See Nga people
- The name of a small ethnic group living in Yunnan and Sichuan Provinces in China. See Mosuo
- Na (tree), Mesua ferrea a tree native to Sri Lanka, India, southern Nepal, Indochina, and the Malay Peninsula.
- Na (surname), a Korean family name
- Na (kana), the な or ナ kana in the Japanese language
- Na (play), a play by the Indian playwright Anand Gandhi
NA may refer to
- Avogadro's number — abbreviated to NA
- Namibia (ISO country code)
- Narcotics Anonymous
- One of several National Alliances
- National Association, the official designation of federally-chartered banks in the United States.
- National Association of Professional Base Ball Players (the sole professional "league" 1871-1875)
- National Association of Professional Baseball Leagues (minor league baseball since December 1901)
- Naturally-aspirated engine (Normally-aspirated engine)
- Naughty America — a pornography company in the United States
- New Africa — a North American Black nationalist group
- Neighborhood association (see neighbourhood)
- Neo-Aramaic languages
- Nestle-Aland
- Neurotics Anonymous
- North America
- North American Airlines — IATA airline designator
- One of several Northern Alliances
- Not Applicable (frequently written "n/a")
- Not Available (frequently written "n/a")
- Nucleic acid
- Numerical aperture — a specification in optical systems
- The Virgin New Adventures series of Doctor Who novels
- Norfolk Academy
- N.A. was a Manhattan(New York) Nightclub, named after its owner Noel Ashman. The club is now closed and the space houses The Plumm. It was once the home of Nell's
nA may stand for:
- Nanoampere, an SI unit of electric current (defined as 10−9 A)
