- Pain
- Paired-Associate Learning
- Panic/Panic Disorders
- Paranoia
- Paraphilia
- Parapsychology
- Parent-Child Relationships
- Parkinson's Disease
- Passive-Aggressive Personality
- Paul J. Meehl
- Pedophilia
- Peer Acceptance
- Peer Mediation
- Peer Pressure
- Perception
- Perfectionism
- Personality
- Personality Development
- Personality Disorders
- Personality Inventory
- Pervasive Developmental Disorder (PDD)
- Philippe Pinel
- Philosophical Psychology
- Phobia
- Phrenology
- Physiological Psychology
- Pierre Marie Félix Janet
- Pierre Paul Broca
- Placebo Effect
- Play
