Feline Leukemia Inhibitory Factor (LIF) is a multifunctional cytokine belonging to the IL-6 family—which includes IL-6, IL-11, oncostatin M (OSM), ciliary neurotrophic factor (CNTF), cardiotrophin-1 (CT-1), cardiotrophin-like cytokine factor 1 (CLCF1), and IL-27—all of which signal through receptor complexes containing the shared gp130 subunit. In cats (Felis catus), LIF binds to the LIF receptor (LIFR) in association with gp130, activating JAK/STAT3, MAPK, and PI3K signaling pathways that regulate cell survival, differentiation, immune modulation, and tissue repair. Feline LIF plays important roles in reproductive biology, particularly in embryo implantation and endometrial receptivity, as well as in hematopoiesis, neural cell survival, and inflammatory regulation. In feline health, LIF may contribute to modulation of inflammatory responses in chronic diseases such as inflammatory bowel disease and neoplasia, where STAT3-mediated signaling influences tissue remodeling and tumor microenvironment dynamics. Dysregulated LIF expression could impact fibrosis, immune tolerance, or tumor progression. As both an immunomodulatory and regenerative cytokine, feline LIF is relevant in studies of reproductive success, stem cell biology, oncology, and cytokine network regulation. Characterization of feline LIF supports comparative investigations into IL-6 family signaling pathways and their roles in inflammation, tissue repair, and disease pathogenesis in both veterinary and human medicine.