Canine Interferon-Gamma (IFN-γ) is a type II interferon produced primarily by activated CD4⁺ and CD8⁺ T lymphocytes and natural killer (NK) cells in dogs (Canis lupus familiaris), where it plays a central role in cell-mediated (Th1-type) immunity against intracellular pathogens. IFN-γ signals through the IFN-γ receptor complex (IFNGR1/IFNGR2), activating JAK/STAT1 pathways and inducing genes involved in macrophage activation, enhanced antigen presentation via upregulation of MHC class I and II molecules, nitric oxide production, and promotion of cytotoxic T-cell responses. In canine health, IFN-γ is critical for defense against pathogens such as Leishmania infantum, Mycobacterium spp., canine distemper virus, and certain tick-borne intracellular organisms, and its expression levels are often associated with protective Th1 immune responses and vaccine efficacy. Dysregulated or insufficient IFN-γ responses can contribute to chronic infection, immune-mediated disease, or altered inflammatory balance. In translational research, dogs serve as valuable spontaneous models for human infectious diseases (e.g., leishmaniasis), autoimmune conditions, and certain cancers, and characterization of canine IFN-γ supports studies of T-cell function, immune modulation, vaccine development, and comparative cell-mediated immunity relevant to both veterinary medicine and human health.