Mouse IL-18 (Interleukin-18) is a pro-inflammatory cytokine belonging to the IL-1 family that plays a central role in innate and adaptive immune responses in mice (Mus musculus). IL-18 is produced primarily by monocytes, macrophages, dendritic cells, epithelial cells, and other tissue-resident cells as an inactive precursor that requires cleavage by caspase-1 following inflammasome activation to become biologically active. Once activated, IL-18 stimulates production of interferon-γ (IFN-γ) by CD4⁺ and CD8⁺ T cells as well as natural killer (NK) cells, thereby promoting Th1-type immune responses and enhancing cell-mediated immunity against intracellular pathogens. In healthy mice, basal IL-18 expression is generally low but increases during bacterial, viral, and parasitic infections, as well as during inflammatory stimulation. Mouse IL-18 has been extensively studied in models of sepsis, colitis, experimental autoimmune encephalomyelitis (EAE), arthritis, metabolic inflammation, and tumor immunity. Depending on context, IL-18 can contribute to protective immunity or to pathological inflammation. In biomedical research, mouse IL-18 serves as a key marker of inflammasome activation and Th1-driven immune responses and is widely used to investigate mechanisms of innate immune signaling and inflammatory disease.