Dolphin IL-17A (Interleukin-17A) is a pro-inflammatory cytokine belonging to the IL-17 family that plays a role in host defense and inflammatory responses in dolphins (e.g., Tursiops truncatus). IL-17A is produced primarily by Th17-like CD4⁺ T cells, as well as by γδ T cells and other innate lymphoid cell 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, and antimicrobial peptides, thereby promoting neutrophil recruitment and enhancing mucosal and barrier immunity in respiratory, gastrointestinal, and dermal tissues. In healthy dolphins, basal IL-17A expression is expected to be low, but levels may increase during bacterial or fungal infections, parasitic infestations, skin lesions, respiratory disease, or systemic inflammatory responses. In marine mammal and comparative immunology research, dolphin IL-17A is of interest for understanding Th17-mediated immunity, host responses to environmental stressors and pathogens, and the balance between protective inflammation and tissue damage in free-ranging and managed populations.