NIA
- Institute of Public Accountants
- Janjgir Naila railway station
- NIAS (disambiguation)
- Nanotechnology Industries Association
- National Immigration Administration
- National Immigration Agency
- National Indoor Arena
- National Infrastructure Commission
- National Institute of Aerospace
- National Institute of Ayurveda
- National Institute on Aging
- National Intelligence Agency (disambiguation)
- National Intelligence Authority
- National Investigation Agency
- National Iraqi Alliance
- National Irrigation Administration
- Nature Improvement Area
- Net income attributable
- Net internal area
- Neural Impulse Actuator
- Nguzo Saba
- Nia (album)
- Nia (charity)
- Nia (fitness)
- Nia (fungus)
- Nia (given name)
- Nias language
- Nigerian Institute of Architects
- Nile Air
- Nimba Airport
- Noi Bai International Airport
- Northern Ireland Assembly
- Nuclear Industry Association
- Philippine
- Project NIA
- SS Nia
- State Intelligence Services (the Gambia)