Rabbit Interleukin-5 (IL-5) is a Th2-associated cytokine produced primarily by activated CD4⁺ T helper 2 (Th2) cells, mast cells, and type 2 innate lymphoid cells in rabbits (Oryctolagus cuniculus), where it plays a central role in eosinophil differentiation, activation, recruitment, and survival. IL-5 is a member of the common beta chain (βc) cytokine family, which also includes IL-3 and granulocyte–macrophage colony-stimulating factor (GM-CSF); these cytokines share the βc receptor subunit and regulate hematopoiesis and myeloid cell development. IL-5 signals through a receptor complex composed of IL-5Rα and the shared βc chain, activating JAK/STAT and MAPK pathways that promote eosinophil maturation in the bone marrow and enhance their effector functions in peripheral tissues. In rabbit health, IL-5 is particularly relevant in parasitic infections, allergic skin conditions, and respiratory inflammation, where elevated IL-5 contributes to eosinophilic infiltration, airway hyperreactivity, and tissue remodeling. Rabbits are widely used as experimental models for asthma and allergic airway disease, and IL-5 plays a key role in driving eosinophilic lung inflammation in these systems. While IL-5–mediated responses support protective immunity against helminths, excessive or sustained IL-5 signaling can promote chronic eosinophilic inflammation and fibrosis. As a biomarker of type 2 immune activation, rabbit IL-5 supports translational research into eosinophil biology, Th1/Th2 immune balance, and development of targeted anti–IL-5 therapies relevant to human allergic and inflammatory disorders.