Terahertz (THz) technology has emerged for biomedical applications such as scanning, molecular spectroscopy, and medical imaging. However, the biological effect of THz radiation is not fully understood. Non-thermal effects of THz radiation were investigated by applying a femtosecond-terahertz (fs-THz) pulse to mouse skin. Analysis of the genome-wide expression profile in fs-THz-irradiated skin indicated that wound responses were predominantly through NFB1- and Smad3/4-mediated transcriptional activation. Repeated fs-THz radiation delayed the closure of mouse skin punch wounds due to up-regulation of transforming growth factor-beta (TGF-). These findings suggest that fs-THz radiation provokes a wound-like signal in skin with increased expression of TGF- and activation of its downstream target genes, which perturbs the wound healing process in vivo.