Equine Interferon-γ (IFN-γ) is a type II interferon cytokine that plays a central role in cell-mediated immunity and regulation of antimicrobial responses in horses (Equus caballus). IFN-γ is primarily produced by activated T helper 1 (Th1) lymphocytes, cytotoxic T cells, and natural killer (NK) cells following stimulation by intracellular pathogens or inflammatory cytokines. Equine IFN-γ binds to the interferon-γ receptor (IFNGR) expressed on many immune and non-immune cells, activating intracellular signaling through the JAK–STAT pathway, particularly STAT1, which induces transcription of interferon-stimulated genes involved in antimicrobial defense, antigen presentation, and immune regulation. In horses, IFN-γ is critical for macrophage activation, enhanced antigen presentation via MHC molecules, and control of intracellular pathogens. In equine health, IFN-γ contributes to immune responses against infectious diseases such as equine herpesvirus and Rhodococcus equi infections. Horses are also used as animal models for respiratory and intracellular bacterial infections, and IFN-γ–mediated immune responses have been studied in foal models of Rhodococcus equi pneumonia, where IFN-γ–driven macrophage activation is important for controlling intracellular bacterial replication, providing insights relevant to both equine infectious disease and comparative studies of pulmonary immunity.