| Acronym | Definition |
|---|
| AEI | American Enterprise Institute |
| AEI | Albert Einstein Institute |
| AEI | Archive of European Integration |
| AEI | ARDA (American Resort Development Association) Education Institute |
| AEI | Australian Education International |
| AEI | Automotive Engineering International |
| AEI | Architectural Engineering Institute (Washington, DC) |
| AEI | Australian Education Index |
| AEI | Alternative Energy Institute |
| AEI | Affiliated Engineers Inc. |
| AEI | American English Institute |
| AEI | Assistance Eligible Individual (COBRA rule change under American Reovery and Reinvestment Act of 2009) |
| AEI | Automatic Equipment Identification |
| AEI | Average Earnings Index |
| AEI | Arab Educational Institute |
| aei | Air Express International |
| AEI | Arts and Exhibitions International |
| AEI | Aircraft Engineers International |
| AEI | Asia Electronics Industry |
| AEI | Associazione Elettrotecnica ed Elettronica Italiana (Italian: Italian Association of Electrical Engineering and Electronics) |
| AeI | Aerosystems International |
| AEI | Audubon Expedition Institute |
| AEI | Albert Ellis Institute |
| AEI | Access Exchange International |
| AEI | Analytical Engineering, Inc. (Indiana) |
| AEI | Asia Europe Institute |
| AEI | Alleanza Evangelica Italiana |
| AEI | Air Emissions Inventory |
| AEI | Automotive Environmental Index (JD Power and Associates) |
| AEI | American Education Institute |
| AEI | Argentina En La Era de La Informacion |
| AEI | Asian Energy Institute |
| AEI | Associated Electrical Industries, Ltd. |
| AEI | Adult Education Initiative |
| AEI | Army Enterprise Infostructure |
| AEI | Association des Études Internationales (French: International Studies Association) |
| AEI | Application Enabling Interface (IBM's term for ALI) |
| AEI | Aide A l'Enfance de l'Inde (Luxembourg) |
| AEI | Atomic Energy Insights |
| AEI | Arts in Education Institute |
| AEI | Alternative Endoscope Instruments |
| AEI | Atelier Experimentation et Instrumentation |
| AEI | Australian Ethical Investment Ltd. |
| AEI | Art Educators of Iowa |
| AEI | Appalachian Education Initiative |
| AEI | Association des Eleves Ingenieurs |
| AEI | After Etch Inspection |
| AEI | Architectural and Engineering Instructions |
| AEI | Agencia Europeia de Imprensa |
| AEI | Association des Etudiants Internationaux (French: International Students Association) |
| AEI | Annular Epidermolytic Ichthyosis |
| AEI | Aerial Exposure Index |
| AEI | Australian Economic Indicators |
| AEI | Artists Embassy International |
| AEI | Accelerated and Enriched Instruction |
| AEI | Advanced Ergonomics, Inc. |
| AEI | American Eye Institute |
| AEI | Application Enhancements Inc. (Toronto, Canada) |
| AEI | Arthur Engineering Inc. |
| AEI | Association of Early Intervention |
| AEI | Alexander Edwards International, Inc. |
| AEI | Association des Étudiants en Informatique |
| AEI | Advanced Environmental Interface, Inc. |
| AEI | Atomic Energy Institute (Moscow) |
| AEI | Amazon Environmental, Inc. |
| AEI | Armament Enhancement Initiative |
| AEI | Aluminium Extrusion Industries (Singapore) |
| AEI | Academia de Evaluación Institucional |
| AEI | Allied Engineers, Inc. |
| AEI | Action Environmental, Inc. |
| AEI | Architect and Engineers, Inc. |
| AEI | Advanced Endovascular Institute |
| AEI | Amusement Enterprises, Inc. |
| AEI | Axe Empowerment Institute |
| AEI | Auxiliar Euro Industrial |
| AEI | Astro Eight Inches |
| AEI | Analyste, Exploitation Informatique (employee group in Québec) |
| AEI | Accountable Equipment Index |
| AEI | AFMC Enterprise Intranet |
| AEI | Azimuth Error Indicator |
| AEI | Audio End Instrument |
| AEI | Angle Error Indicator |
| AEI | Ampul Electric, Inc. |
| AEI | l'Action Educative et Innovante |
| AEI | Average Efficiency Index |
| AEI | Air Emissions Industry |
| AEI | Avalanche Electron Injection |
| AEI | Ateliers d’Échanges et d’Innovation |
| AEI | Alimentation en Eau Industrielle |
| AEI | Alianza Espiritualista Internacional (Spanish) |
| AEI | Alpes Embrun Immobilier (French real estate agency) |
| AEI | Automatisme et Electricité Industrielle (French electrical equipment manufacturer; est. 1988) |
| AEI | Alliance Ecologiste Indépendante (French: Independent Ecologist Alliance) |
| AEI | American Entomological Institute (Gainesville, FL) |
| AEI | American Eagle Instruments (Missoula, MT) |
| AEI | Agence Européenne Immobilière (French: European Real Estate Agency; EU) |
| AEI | Alpha Europe Immobilier (French real estate agency) |
| AEI | Advanced Energy Initiative |
| AEI | Active Enterprise Intelligence (software) |
| AEI | Advanced Explorations, Inc. (Canada) |