| Acronym | Definition |
|---|
| CEI | Competitive Enterprise Institute |
| CEI | Conferenza Episcopale Italiana (Italian bishop conference) |
| CEI | Central European Initiative |
| CEI | Comitato Elettrotecnico Italiano (Italian Electrotechnical Committee) |
| CEI | Comunidad de Estados Independientes (Spanish: Commonwealth of Independent States) |
| CEI | Commission Electrotechnique Internationale (International Electrotechnical Commission) |
| CEI | Corporate Equality Index |
| CEI | Computational Engineering International |
| CEI | Coastal Enterprises, Inc. |
| CEI | Career Education Institute |
| CEI | Centro de Estudios Internacionales (Spanish: Center for International Studies; Spain) |
| CEI | Consumer Education Initiative (recycling) |
| CEI | Center for Entrepreneurship and Innovation (University of Florida) |
| CEI | Comparably Efficient Interconnection |
| CEI | Cleveland Electric Illuminating |
| CEI | Clean Energy Initiative |
| CEI | Construction Engineering & Inspection |
| CEI | Connection Endpoint Identifier (UNI 3.0) |
| CEI | Center for Emerging Issues |
| CEI | Contract End Item |
| CEI | Compliance Evaluation Inspection |
| CEI | Call for Expression of Interest |
| CEI | Conducted Electromagnetic Interference |
| CEI | Computer Education Institute |
| CEI | Council of Engineering Institutions |
| CEI | Coastal Environments Inc |
| CEI | Chiang Rai, Thailand - Chiang Rai (Airport Code) |
| CEI | Committee on Environmental Improvement |
| CEI | Certified Electrical Inspector (International Association of Electrical Inspectors) |
| CEI | Configuration End Item (NASA) |
| CEI | Cholinesterase Inhibitor |
| CEI | Comparatively Efficient Interconnection |
| CEI | Communications & Entertainment Inc. (Atlanta, GA) |
| CEI | Committee on Environmental Issues |
| CEI | Combustion Engineering Inc. |
| CEI | Commodity Exchange, Inc. |
| CEI | Centre for Environmental Information (Russia) |
| CEI | Chemistry Education International |
| CEI | California Electrical Inspectors |
| CEI | Construction Equipment Institute |
| CEI | Connected Element Interferometry |
| CEI | critical employment indicator (US DoD) |
| CEI | Competitive Edge, Inc. (Peachtree City, GA) |
| CEI | Capital Equipment Inventory |
| CEI | Communications Electronics Intelligence |
| CEI | Configured End Item |
| CEI | Communications Electronics Instruction |
| CEI | COMINT/ELINT Integration |
| CEI | Centennial Energy Institute (Centennial College, Toronto, Canada) |
| CEI | Comprehensive Emissions Inventory |
| CEI | Canadian External Interface |
| CEI | Communications Electronics Installation |
| CEI | Critical Equipment Indicator |
| CEI | Corporación Eléctrica Industrial (Spanish, Guatemala) |
| CEI | College Equality Index (cultural climate index) |
| CEI | Centro de Enriquecimiento de la Inteligencia (Guatemala) |