The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Pace, D (16 members)
- Pages with broken file links (3 members)
- Pages with template loops (1 member)
- Palfreyman, N (4 members)
- Pedagogy (2 members)
- Pelnar, H (4 members)
- People (10 members)
- Person (1 member)
- Pettit, J (2 members)
- Phillips, J (1 member)
- Philosophy (2 members)
- Physics (3 members)
- Pilachowski, C A (1 member)
- Pinnow, E (1 member)
- Political science (3 members)
- Poster (1 member)
- Practice (5 members)
- Predicate logic (1 member)
- Presentation (1 member)
- Priss, U (0 members)
- Professional education (2 members)
- Psychology (12 members)
- PublicationType (6 members)
- PublicationYear (26 members)
- PublishedWork (194 members)
- Quintanilla, V D (1 member)
- Quiring, B (0 members)
- Rankin, M (0 members)
- Rathburn, M (2 members)
- Reading (2 members)
- Rechter, S (1 member)
- Redmond, P (1 member)
- Rehrey, G (1 member)
- Reinmann, G (0 members)
- Report (1 member)
- Review article (4 members)
- Riegler, P (23 members)
- Robbins, A (1 member)
- Roberts, P (0 members)
- Robinson, W (1 member)
- Rosenthal, J (1 member)
- Rouse, M (1 member)
- Rubin, M B (1 member)
- Russian language (1 member)
- Saam, J (1 member)
- Saunders, T (1 member)
- Scarnati, B (1 member)
- Schlegel, W M (0 members)
- Schlierkamp, K (1 member)
- Schreiber, S (2 members)
