Feline interleukin-25 (IL-25), also known as IL-17E, is a member of the IL-17 cytokine family and functions as a key regulator of type 2 immune responses through signaling via the IL-17RA/IL-17RB receptor complex and downstream NF-κB and MAPK pathways. In cats, IL-25 is expected to promote Th2-associated cytokine production (including IL-4, IL-5, and IL-13), eosinophil recruitment, and mucosal immune activation, playing an important role in defense against parasitic infections while also contributing to allergic and inflammatory conditions. In feline health, IL-25 is particularly relevant in diseases characterized by type 2 immune polarization, such as feline asthma, allergic dermatitis, eosinophilic granuloma complex, and inflammatory bowel disease. Dysregulated IL-25 signaling may exacerbate airway hyperreactivity, skin inflammation, and gastrointestinal eosinophilia, mirroring its role in comparable human conditions including asthma, atopic dermatitis, chronic rhinosinusitis, and food allergy. Because cats naturally develop spontaneous allergic airway disease and chronic inflammatory disorders within an intact immune system, feline IL-25 serves as both a potential biomarker and therapeutic target in veterinary medicine, as well as a valuable comparative model for studying type 2–driven inflammatory diseases across species.