Vittorio Marchi (30 May 1851, Novellara – 12 May 1908, Iesi) was an Italian neurologist and histologist.He studied pharmaceutical chemistry and medicine at the University of Modena, earning his doctorate in 1882. He was head of the histology laboratory at the psychiatric hospital of Reggio Emilia, and later director of the primary medical hospital in Iesi.He was the creator of a popular osmium-based staining method ("Marchi stain") for the demonstration of degenerating nerve fibers.