P-selectin is a protein that in humans is encoded by the SELP gene.
P-selectin functions as a cell adhesion molecule (CAM) on the surfaces of activated endothelial cells, which line the inner surface of blood vessels, and activated platelets. In unactivated endothelial cells, it is stored in granules called Weibel-Palade bodies. In unactivated platelets P-selectin is stored in α-granules.