| Acronym | Definition |
|---|
| MAI | Mail (File Name Extension) |
| MAI | Multilateral Agreement on Investment |
| MAI | Maius (Latin: May) |
| MAI | Ministério da Administração Interna (Portugal) |
| MAI | Mycobacterium Avium-Intracellulare |
| MAI | Multiple Access Interference |
| MAI | Ministerul Administratiei si Internelor (Romanian) |
| MAI | Minority AIDS Initiative |
| MAI | Member, Appraisal Institute (real estate) |
| MAI | Moscow Aviation Institute |
| MAI | Market for Alternative Investment (Second Board on Thailand's Exchange) |
| MAI | Mean Annual Increment (forestry) |
| MAI | Monash Asia Institute |
| MAI | Manufacturers' Association of Israel |
| MAI | Media Action International |
| MAI | Made As Instructed |
| MAI | Middleware-Application Interaction |
| MAI | Medical Action Industries Inc. (Brentwood, NY) |
| MAI | Median Area Income |
| MAI | Multilevel Assessment Instrument |
| MAI | Migration and Asylum Initiative (now part of MARRI) |
| MAI | Military Assistance Institute |
| MAI | Major Automated Information |
| MAI | Measurement, Analysis and Improvement |
| MAI | Myanmar Airway International |
| MAI | Medication Assisted Intubation |
| MAI | Management Assistance Incorporated |
| MAI | Material Annex Item |
| MAI | General Appraisal Member of the Appraisal Institute (formerly Member Appraisal Institute) |
| MAI | Multiple Action Interaction |
| MAI | Mesna, Adriamycin, and Ifosfamide (chemotherapy regimen) |
| MAI | Master Assessment Index |