- Adecco
- Adel Visi
- Adelaide United
- Adeline Andre
- Adelphi University
- Adelta Photonic Private Company Limited
- Adept Technology, Inc.
- Adesa Inc
- Adeshwar Cotton Industries
- ADF Foods Industries
- Adhinath Textiles
- Adhunik Metaliks Limited
- Adhunik Synthetics
- Adhunik Yarns
- Adi Rasayan
- Adidas by Stella McCartney (designer)
- Adinath Bio-Labs
- Adinath Exim Resources
- Adirondack Council
- Adirondack Park Agency
- Adithya Alkaloids
- Adithya Aqua Culture
- Aditya Birla Group
- Aditya Electro Communications
- Aditya Exports
- Aditya Forge
- Aditya Gears
- Aditya International
- Aditya Ispat
- Aditya Lime Industries
- Aditya Mills
- Aditya Polymers
- Aditya Spinners
- Adknowledge
- Adlabs Films
- Adlabs Studios
- AdMeld
- Administaff, Inc.
- Admiral Group
- AdMob
- ADO Den Haag
- Adobe Systems
- Ador Fontech
- Ador Powertron
- Ador Technopak
- Ador Welding
- Adore Multiproducts
- ADP Employer Services
- ADS Diagnostic
- AdSense
- ADTRAN, Inc.
- Adult Swim
- ADVANCE AUTO PARTS
- Advance Bio-Coal (India)
- Advance Developing Markets
- Advance Multitech
- Advance Petrochemicals
- Advanced Analogic Technologies, Inc.
- Advanced Energy Industries, Inc.
- Advanced Magnetics, Inc.
- Advanced Medical Optics, Inc.
- Advanced Micronic Devices
- Advanced Semiconductor Engineering, Inc.
- Advani Hotels and Resorts (India)
- ADVANTA Corp.
- Advanta India
- ADVANTAGE ENERGY INCOME FUND
- Advent Computer Services
- Advent Software, Inc.
- Adventist Development and Relief Agency
- ADVENTRX Pharmaceuticals Inc.
- Adventure Soft
- Advertising Council
- Advik Laboratories
- Advisory Board Company
- ADVO, Inc.
- Advocates for Children
- AEC (India)
- AEC Enterprises
- AECID
- AEG Live
- Aegis Defence Services
- Aegis Group
- Aegis Logistics
- Aegon NV
- AEGON Religare Life Insurance Company Limited
- AEK Athens
- Aekta (Company)
- Aeon Group
- Aeonian Investments