Swine IL-17F (Interleukin-17F) is a pro-inflammatory cytokine of the IL-17 family that plays a key role in host defense and inflammatory regulation in pigs (Sus scrofa). IL-17F is produced primarily by Th17 CD4⁺ T cells, as well as by γδ T cells—which are prominent in swine—and other innate lymphoid populations following microbial infection or immune stimulation. It signals through the IL-17 receptor complex (IL-17RA/IL-17RC) to induce expression of pro-inflammatory cytokines (e.g., IL-6, TNF-α), chemokines such as CXCL8, and antimicrobial peptides, thereby promoting neutrophil recruitment and enhancing mucosal barrier immunity in the respiratory and gastrointestinal tracts. IL-17F frequently acts synergistically with IL-17A to amplify Th17-driven inflammatory responses. In healthy pigs, basal IL-17F expression is generally low, but levels increase during bacterial and fungal infections, parasitic infestations, enteric inflammation, and respiratory disease. Swine IL-17F has been implicated in immune responses to pathogens such as porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus, Actinobacillus pleuropneumoniae, and enterotoxigenic Escherichia coli. In veterinary and translational research, IL-17F serves as a biomarker of Th17-mediated immune activation and neutrophilic inflammation, providing insight into host–pathogen interactions, mucosal immunity, and vaccine-induced immune responses in porcine health and biomedical models.