Swine TWEAK (TNF-like Weak Inducer of Apoptosis, also known as TNFSF12) is a cytokine belonging to the tumor necrosis factor (TNF) superfamily, which includes related ligands such as TNF-α, Fas ligand (FasL), CD40 ligand (CD40L), TRAIL, and RANKL that regulate immune signaling, apoptosis, and tissue remodeling. In pigs (Sus scrofa), TWEAK is produced primarily by immune cells such as macrophages, monocytes, dendritic cells, and T lymphocytes, and can also be expressed by endothelial cells and various tissue cells during inflammation or tissue injury. TWEAK exerts its biological effects mainly through binding to its receptor Fn14 (fibroblast growth factor–inducible 14, TNFRSF12A), activating intracellular signaling pathways including NF-κB and MAPK, which regulate cell proliferation, apoptosis, inflammatory cytokine production, and tissue remodeling. In swine physiology, the TWEAK–Fn14 signaling axis contributes to immune responses, tissue repair, and regulation of inflammatory processes following infection or cellular damage. Because pigs are widely used as large-animal models for human inflammatory disease, regenerative biology, and cardiovascular research, characterization of swine TWEAK supports studies of TNF superfamily signaling, immune regulation, and mechanisms of tissue injury and repair relevant to both veterinary medicine and translational biomedical research.