- Palko v. Connecticut
- Payne v. Tennessee
- Penry v. Lynaugh
- Planned Parenthood of Central Missouri v. Danforth
- Planned Parenthood of Southeastern Pennsylvania v. Casey
- Plessy v. Ferguson
- Plyler v. Doe
- Pollock v. Farmers' Loan & Trust Company
- Powell v. Alabama
- Prigg v. Pennsylvania
- Puerto Rico v. Branstad
