Mouse CXCL4 (C-X-C motif chemokine ligand 4), also known as Platelet Factor 4 (PF4), is a CXC chemokine belonging to the platelet chemokine subgroup of the CXC chemokine family and is primarily released from the α-granules of activated platelets. In mice (Mus musculus), CXCL4 is produced mainly by platelets and megakaryocytes and is rapidly released during platelet activation, vascular injury, or inflammatory responses. CXCL4 plays important roles in hemostasis, modulation of inflammatory signaling, and regulation of leukocyte recruitment, influencing the activity of monocytes, neutrophils, macrophages, and endothelial cells through interactions with cell-surface glycosaminoglycans and chemokine receptors. In murine biology, CXCL4 has been widely studied in experimental models of thrombosis, atherosclerosis, and inflammatory disease, where platelet-derived CXCL4 contributes to platelet–leukocyte interactions, vascular inflammation, and development of atherosclerotic lesions. Mouse models lacking Cxcl4/Pf4 or using platelet-specific manipulations have helped clarify how CXCL4 regulates immune–coagulation crosstalk and vascular inflammation, making mouse CXCL4 an important molecule in studies of platelet biology, cardiovascular disease, and inflammatory signaling.