- Aetna Insurance Co.
- Aetna of Weston, Florida
- Aetna Volunteer Council
- Aetna, Inc.
- Affinity Health System
- Affordable Pet Care P.C.
- AFGE Local 3721
- AFL-CIO Unions
- AFLAC
- AFLAC Associate
- AFLAC, Inc.
- African American Chamber of Commerce of Central Florida
- African-American Women's Clergy Association
- Africare
- Afro-American Historical and Genealogical Society
- AftersSix
- Agape Senior
- Agenda USA
- Agfa Corporation
- Agilent Technologies Inc.
- AgilQuest Corp.
- Agilysys
- Agnesian Healthcare - St. Agnes Hospital
- Agriculture Research Service, Wyndmoor
- Aguirre Corporation
- AHN Grove City
- Ahwatukee Foothills YMCA
- AI Group
- Aiken Regional Medical Center
- AIKO
- AIM, Inc.
- Ainahau O Kaleponi Hawaiian Civic Club
- Air Conditioning Contractors of America
- Air Force Association
- Air Force Enlisted Village
- Air Force Information Warfare
- Air Line Pilots Association International
- Air Master
- Air Methods Corp.
- Air-Conditioning and Refrigeration Institute
- Airport Consultants Council
- Airport Plaza Hotel Seattle
- AIS
- Ajilon
- Akoya
- Akron Children's Hospital
- Akron General Medical Center
- Akron Racers Foundation
- Alabama Campaign to Prevent Teen Pregnancy
- Alabama Council of Association Executives