AEI
- AEI Music Network Inc.
- Adelaide Educational Institution
- Aei (trigraph)
- Albert Einstein Institution
- Alliance for European Integration
- American Enterprise Institute
- Architectural Engineering Institute
- Archive of European Integration
- Associated Electrical Industries
- Atomic Energy Organization of Iran
- Automatic Equipment Identification
- Average Earnings Index
- Average Earnings Index (horse racing)
- EAI (disambiguation)
- Max Planck Institute for Gravitational Physics
- State Research Agency