Feline Interleukin-13 (IL-13) is a Th2-associated cytokine produced primarily by activated CD4⁺ T helper 2 (Th2) cells and other type 2 immune cells in cats (Felis catus), where it plays a central role in allergic inflammation, mucosal immunity, and tissue remodeling. IL-13 signals through receptor complexes composed of IL-13Rα1 and IL-4Rα, activating JAK/STAT6 pathways that regulate gene expression involved in alternative macrophage activation, IgE-associated responses, mucus production, and modulation of pro-inflammatory cytokine signaling. In feline health, IL-13 is particularly relevant in allergic and chronic inflammatory conditions such as feline asthma, atopic dermatitis, eosinophilic granuloma complex, and inflammatory bowel disease, where elevated Th2 cytokine activity contributes to airway hyperreactivity, eosinophilic infiltration, and tissue remodeling. IL-13 may also influence immune responses during parasitic infections and chronic viral diseases by shaping Th1/Th2 balance. As a biomarker of type 2 immune polarization, feline IL-13 is important in studies of allergic disease pathogenesis, vaccine responses, and immune regulation. In translational research, cats serve as valuable spontaneous models for human asthma and allergic airway disease, and characterization of feline IL-13 supports comparative investigations into Th2-mediated inflammation, airway remodeling, and development of targeted anti-cytokine therapies relevant to both veterinary and human medicine.