Canine CCL5 (C–C motif chemokine ligand 5, also known as RANTES – Regulated upon Activation, Normal T cell Expressed and Secreted) is a proinflammatory chemokine that regulates immune cell recruitment, inflammatory signaling, and antiviral responses in dogs (Canis lupus familiaris). CCL5 belongs to the CC chemokine family, which also includes CCL3 (MIP-1α), CCL4 (MIP-1β), and CCL2 (MCP-1), chemokines that control leukocyte trafficking during immune activation. In dogs, CCL5 is produced primarily by activated T lymphocytes, macrophages, dendritic cells, platelets, and epithelial cells in response to infection, inflammatory stimuli, or tissue injury, and exerts its biological effects mainly through binding to the chemokine receptors CCR1, CCR3, and CCR5, promoting chemotaxis and activation of T cells, monocytes/macrophages, eosinophils, and natural killer (NK) cells at sites of inflammation. CCL5 contributes to immune responses against viral and bacterial pathogens and is involved in chronic inflammatory and immune-mediated diseases such as canine atopic dermatitis and inflammatory bowel disease. Because dogs naturally develop several diseases that resemble human conditions, including allergic skin disease, inflammatory bowel disease, and certain cancers, canine CCL5 is also studied in comparative animal models of human inflammatory and immune-mediated disorders, helping to understand chemokine-driven leukocyte recruitment, tumor microenvironment signaling, and therapeutic targeting of the CCL5–CCR5 pathway.