Canine interleukin-25 (IL-25), also known as IL-17E, is a member of the IL-17 cytokine family and functions as a key promoter of type 2 immune responses through signaling via the IL-17RA/IL-17RB receptor complex, activating downstream NF-κB and MAPK pathways. In dogs, IL-25 is expected to drive Th2-associated cytokine production—including IL-4, IL-5, and IL-13—leading to eosinophil recruitment, IgE-associated responses, and enhanced mucosal immunity. In canine health, cIL-25 is particularly relevant in allergic and inflammatory diseases characterized by type 2 immune polarization, such as canine atopic dermatitis, allergic otitis, food hypersensitivity, eosinophilic gastrointestinal disease, and canine asthma–like airway inflammation. While IL-25 supports protective immunity against parasitic infections, dysregulated signaling may contribute to chronic pruritus, skin barrier dysfunction, airway hyperreactivity, and gastrointestinal inflammation. Because dogs naturally develop spontaneous allergic and inflammatory disorders within an intact immune system, canine IL-25 represents both a potential biomarker and therapeutic target in veterinary medicine, as well as a valuable comparative model for studying type 2–driven diseases analogous to human asthma, atopic dermatitis, and allergic gastrointestinal disorders.