Canine Interleukin-8 (IL-8), also known as CXCL8, is a potent pro-inflammatory chemokine that plays a central role in innate immune responses in dogs (Canis lupus familiaris) by mediating neutrophil chemotaxis, activation, and migration to sites of infection or tissue injury. Produced by macrophages, epithelial cells, endothelial cells, and fibroblasts in response to microbial stimuli and inflammatory cytokines, canine IL-8 signals primarily through CXCR1 and CXCR2 receptors to activate downstream pathways that promote leukocyte recruitment and amplification of acute inflammation. Elevated IL-8 expression is associated with a variety of canine diseases, including bacterial pneumonia, canine influenza, parvoviral enteritis, pyometra, atopic dermatitis, osteoarthritis, and inflammatory bowel disease, where excessive neutrophilic infiltration can contribute to tissue damage and chronic inflammation. As a biomarker, IL-8 is useful for assessing inflammatory status and monitoring therapeutic response in clinical veterinary medicine. Importantly, dogs serve as valuable spontaneous animal models for human diseases characterized by neutrophil-driven pathology, including asthma (canine chronic bronchitis), inflammatory bowel disease, atopic dermatitis, osteoarthritis, sepsis, and certain cancers such as osteosarcoma and lymphoma. Characterization of canine IL-8 in these naturally occurring models enhances translational research into chemokine-mediated immune cell trafficking, chronic inflammation, tumor microenvironment biology, and the development of targeted anti-inflammatory and immunomodulatory therapies relevant to both canine and human health.