Mouse interleukin-25 (IL-25), also known as IL-17E, is a member of the IL-17 cytokine family and functions as a potent inducer of type 2 immune responses through signaling via the IL-17RA/IL-17RB receptor complex, activating NF-κB and MAPK pathways. In mice, IL-25 promotes the expansion and activation of Th2 cells and type 2 innate lymphoid cells (ILC2s), driving production of IL-4, IL-5, and IL-13, eosinophilia, IgE class switching, and mucus production. It plays a central role in protective immunity against helminth infections but is also a key mediator of allergic inflammation in widely used murine models of asthma, atopic dermatitis, food allergy, and eosinophilic gastrointestinal disease. Dysregulated IL-25 signaling in mouse models contributes to airway hyperresponsiveness, goblet cell hyperplasia, and chronic tissue inflammation, making it a critical experimental target for studying type 2–driven pathology. Because murine systems are foundational for mechanistic immunology research, mouse IL-25 serves as an essential tool for dissecting type 2 immune pathways and for preclinical evaluation of biologics targeting allergic and inflammatory diseases relevant to human health.