Peptide modification enhances the physicochemical properties of peptides by introducing specific chemical groups or structural adjustments, but achieving site-selective modification remains a significant challenge. Recently, the selective functionalization of peptides, particularly through metal catalysis, has attracted growing attention. Gold catalysts, in particular, have emerged as a powerful tool due to their high catalytic efficiency, exceptional stability, and biocompatibility. Gold-catalyzed peptide modifications can improve target specificity, modulate protein-protein interactions, and enable precise control over functional group incorporation. This review focuses on the latest advancements in gold-catalyzed site-selective functionalization of peptides, by providing a detailed overview of these developments, we aim to increase understanding in the field and encourage further exploration of gold-mediated peptide modifications.