NECA or Neca may refer to:
- Neca (footballer) (born 1979), real name João Alexandre Duarte Ferreira Fernandes, Portuguese footballer
- NECA Project, Net Environment for Embodied Emotional Conversational Agents
- National Entertainment Collectibles Association, an American merchandise licensee of film and television for the enthusiast market
- National Electrical Contractors Association, an American trade association
National Exchange Carrier Association, an American association of telephone common carriers
- NECA Show, electrical construction industry’s trade show since 1901
- North East Combined Authority, a local government body in North East England
- NECA Company, drug and alcohol charity in the United Kingdom
- 5′-(N-ethylcarboxamido)adenosine (NECA), a reference agonist for adenosine G protein-coupled receptors (GPCRs).
- Nitrous Oxide Emission Control Area (NECA), sea areas with regulated nitrous oxides emission caps
João Alexandre Duarte Ferreira Fernandes (born 31 December 1979), known as Neca, is a Portuguese footballer who plays for C.D. Pinhalnovense as a midfielder.
He amassed Primeira Liga totals of 225 games and 29 goals over the course of 12 seasons, representing in the competition Belenenses, Vitória de Guimarães, Marítimo and Vitória de Setúbal. He also competed professionally in Turkey.