| Acronym | Meaning |
| MAC | Chief Machine Accountant (naval rating) |
| MAC | Macau (ISO Country code) |
| MAC | Magnetic Anomaly Concealment |
| MAC | Main Automation Contractor |
| MAC | Mainland Affairs Council (Taiwan) |
| MAC | Maintenance Action Code |
| MAC | Maintenance Administration Center |
| MAC | Maintenance Allocation Chart |
| MAC | Maintenance Availability Computer |
| MAC | Major Area Commander |
| MAC | Management Action Center |
| MAC | Management Ad Hoc Committee |
| MAC | Management Advisory Committee |
| MAC | Management Advisory Council (FAA) |
| MAC | Management and Administrative Computing |
| MAC | Maneuver Area Command |
| MAC | Mapping and Analysis Center (FEMA) |
| MAC | Marginal Abatement Cost (curve; metric of costs of complying with Kyoto Protocol for reducing greenhouse gases) |
| MAC | Marine Amphibious Corps (est. 1942) |
| MAC | Maritime Area Commander |
| MAC | Market Access and Compliance (US Department of Commerce) |
| MAC | Material Accountability and Control |
| MAC | Material Accounting Center |
| MAC | Material Accumulation Costing |
| MAC | Material Adverse Change |
| MAC | Materiel Acquisition Command |
| MAC | Maximum Amount Contributable (US IRS) |
| MAC | Measurement and Analysis Center |
| MAC | Medicaid Authorization Card |
| MAC | Medical Affirmative Claims |
| MAC | Medicare Administrative Contractor |
| MAC | Mediterranean Air Command (WWII) |
| MAC | Membrane Attack Complex |
| MAC | Men's Advisory Counsel/Committee (prisons) |
| MAC | Metropolitan Airports Commission |
| MAC | Mexican-American Commission |
| MAC | Michigan Administrative Code |
| MAC | Micromechanics Analysis Code (US NASA software) |
| MAC | Military Affairs Council |
| MAC | Military Aircraft Command |
| MAC | Military Airlift Command (US Air Force) |
| MAC | Military Armament Corporation (produced Mac 10&11 SMGs) |
| MAC | Military Assistance Command |
| MAC | Mine Action Center |
| MAC | Minister’s Approval Certificate (UK) |
| MAC | Ministry of Agriculture and Cooperatives |
| MAC | Mission Assignment Coordinator |
| MAC | Mission Assurance Category |
| MAC | Mitigation Assistance Clinic (US FEMA) |
| MAC | MIUW Attack Craft |
| MAC | Mixed Armistice Commission |
| MAC | Mobility Augmentation Company |
| MAC | Mobility Augmentation Company (US Army) |
| MAC | Monetary Affairs Committee (East African Community) |
| MAC | Monitoring Advisory Committee (various locations) |
| MAC | Monitoring and Analysis Coordinator (US FEMA) |
| MAC | Months After Contract |
| MAC | Mortuary Affairs Coordinator |
| MAC | Motor Ambulance Convoy |
| MAC | Multi Agency Committee (various locations) |
| MAC | Multi Aircraft Control (aviation technology) |
| MAC | Multi-Agency Coordinating Entity |
| MAC | Multi-Sensor Air Campaign |
| MAC | Multi-Static Active Coherent (US Navy) |
| MAC | Multiple Access Contract |
| MAC | Multiple Award Contracts |
| MAC | Multiplying Accumulator |
| MAC | Municipal Advisory Council |
| MAC | Municipal Amateur Coordinator |
| MAC | Munitions Assembly Conveyor |