- NCDT
- New Category Development Team
- NCWM
- National Conference on Weights and Measures
- NEDC
- New European Driving Cycle
- NESCAUM
- North East States for Co-ordinated Air Use Management
- NGEO
- Natural Gas Engine Oil
- NGLI
- National Lubricating Grease Institute (USA)
- NGO
- Non-Governmental Organisation
- NGVA
- Natural Gas Vehicle Association
- NHTSA
- National Highway Traffic Safety Administration
- NMMA
- National Marine Manufacturers Association
- NMOG
- Non-Methane Organic Gases
- NOACK
- Apparatus/Method for Volatility Measurement
- NOx
- Nitrous Oxides
- NREL
- National Renewable Energy Laboratory
- NSF
- NSF International – public health and safety organisation
- NSPA
- NATO’s Integrated Logistics and Services Provider Agency
