Guinea pig IL-17A (Interleukin-17A) is a pro-inflammatory cytokine belonging to the IL-17 family that plays an important role in host defense and inflammatory responses in guinea pigs (Cavia porcellus). IL-17A is produced primarily by Th17 cells, as well as by γδ T cells and other innate lymphoid populations, in response to microbial infection and immune stimulation. It acts on epithelial, endothelial, and stromal cells to induce the expression of pro-inflammatory cytokines, chemokines (such as CXCL8), and antimicrobial peptides, thereby promoting neutrophil recruitment and enhancing mucosal and barrier immunity, particularly in the respiratory tract. In healthy guinea pigs, basal IL-17A expression is typically low, but levels increase during bacterial infection, allergic airway inflammation, and experimental immune challenge. In biomedical research, guinea pig IL-17A is especially relevant in models of tuberculosis (Mycobacterium tuberculosis), asthma, and allergic airway disease, where Th17-mediated responses contribute to neutrophilic inflammation and granuloma formation. Characterization of IL-17A in guinea pigs provides valuable insight into mucosal immunity, host–pathogen interactions, and inflammatory mechanisms in translational respiratory and infectious disease research.