| AA | Achievement Age | |
| AAAP | American Association of Applied Psychology | |
| AAAP | American Association for Applied Psychology | |
| AAAS | American Association for the Advancement of Science | |
| AABP | American Academy of Behavioral Psychology | |
| AAP | Association for the Advancement of Psychology | |
| AAPB | Association for Applied Psychophysiology and Biofeedback | |
| AAPI | APPIC Application for Psychology Internships | |
| AAPP | American Association of Pain Psychology | |
| AASI | Abel Assessment for Sexual Interest | |
| ABA | Applied Behavioral Analysis | |
| ABBCP | American Board of Behavioral and Cognitive Psychology | |
| ABBP | American Board of Behavioral Psychology | |
| ABBP | Acceptance Based Behavioral Therapy | |
| ABCP | American Board of Clinical Psychology | |
| ABMP | American Board of Medical Psychology | |
| ABPP | American Board of Professional Psychology | |
| ABPS | American Board of Psychological Specialties | |
| ABRP | American Board of Rehabilitation Psychology | |
| ABSP | American Board of Sport Psychology | |
| ABSP | American Board of School Psychology | |
| ACAP | Asian Congress of Applied Psychology | |
| ACAP | Australian College of Applied Psychology | |
| ACAPS | Appalachian Counseling And Psychological Services | |
| ACCEPT | Association for Community Counselling Education and Psychological Training | |
