- Attention Deficit/Hyperactivity Disorder (ADHD)
- Attitude and Behavior
- Attitudes and Attitude Change
- Attraction, Interpersonal
- Attribution Theory
- Authoritarian Personality
- Autism
- Autoeroticism
- Autonomic Nervous System
- Aversive Conditioning
- Avoidance Learning
- Avoidant Personality
- B. F. Skinner
- Bärbel Inhelder
- Battered Child Syndrome
- Bayley Scales of Infant Development
- Behavior Modification
- Behavior Therapy
- Behaviorism
- Bender-Gestalt Test
- Benjamin Rush
- Benjamin Spock
- Bilingualism/Bilingual Education
- Binocular Depth Cues
- Biofeedback
- Bipolar Disorder
- Birth 3
- Birth Order
- Birth Trauma
- Bisexuality
