Canine CCL3 (C-C motif chemokine ligand 3, also known as MIP-1α, macrophage inflammatory protein-1 alpha) is a pro-inflammatory chemokine that plays a key role in recruitment and activation of immune cells during inflammatory and infectious responses in dogs (Canis lupus familiaris). CCL3 primarily signals through the CCR1 and CCR5 receptors, promoting chemotaxis of monocytes, macrophages, dendritic cells, natural killer (NK) cells, and activated T lymphocytes to sites of infection or tissue injury. In dogs, CCL3 is produced by activated macrophages, dendritic cells, epithelial cells, and lymphocytes in response to inflammatory stimuli such as microbial products and cytokines including TNF-α and IL-1β. CCL3-mediated immune cell recruitment contributes to host defense in infectious diseases and inflammatory conditions such as canine leishmaniasis, bacterial infections, and immune-mediated inflammatory disorders, where monocyte and T cell infiltration supports pathogen clearance and immune activation. However, excessive or prolonged CCL3 expression may contribute to chronic inflammation and tissue damage. CCL3 is also studied in canine cancers such as lymphoma and mast cell tumors, where chemokine-driven immune cell infiltration can influence tumor microenvironment dynamics. As a regulator of leukocyte trafficking and inflammatory signaling, canine CCL3 is important for studies of host–pathogen interactions, immune regulation, and disease pathogenesis in both veterinary and comparative biomedical research.