Swine CCL17 (C-C motif chemokine ligand 17), also known as thymus and activation-regulated chemokine (TARC), is a member of the CC chemokine family that regulates Th2-associated immune responses in pigs (Sus scrofa). CCL17 is produced primarily by dendritic cells, macrophages, endothelial cells, and epithelial cells in response to inflammatory and type 2–associated cytokines. It functions predominantly through the CCR4 receptor to promote chemotaxis and activation of Th2 lymphocytes and regulatory T cells, contributing to adaptive immune polarization and modulation of inflammatory responses. In healthy swine, basal CCL17 expression is generally low, but levels may increase during parasitic infections, allergic-type inflammation, respiratory disease, enteric infection, or experimental immune stimulation. In veterinary and translational research, swine CCL17 is of interest in studies of helminth immunity, mucosal immune regulation, vaccine-induced immune polarization, and respiratory disease models such as porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza. Characterization of CCL17 in pigs provides valuable insight into Th2-skewed immune responses and chemokine-mediated T cell trafficking in both agricultural and biomedical research settings.