Hamster Interleukin-13 (IL-13) is a Th2-associated cytokine produced primarily by activated CD4⁺ T helper 2 (Th2) cells and other type 2 immune populations in hamsters (including Mesocricetus auratus and Phodopus spp.), where it plays a central role in regulating 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 promote alternative macrophage activation, mucus production, IgE-associated immune responses, and suppression of pro-inflammatory cytokine signaling. In hamster health and research, IL-13 is particularly relevant in experimental models of respiratory viral infections such as SARS-CoV-2, where type 2 cytokine responses may influence airway inflammation and tissue repair, as well as in parasitic infection models where Th2 polarization supports helminth clearance. Dysregulated IL-13 expression can contribute to airway hyperreactivity, fibrosis, or chronic inflammatory pathology. Because hamsters are widely used as small-animal models for COVID-19, influenza, and parasitic diseases, characterization of hamster IL-13 supports studies of Th1/Th2 immune balance, cytokine-driven lung pathology, vaccine responses, and development of targeted anti-cytokine therapies relevant to human allergic and respiratory diseases.