Gaetano Perusini (24 February 1879 – 8 December 1915) was an Italian physician. He was the pupil and colleague of Alois Alzheimer and contributed to the definition of Alzheimer's disease. In 1915 he joined the Italian army without disclosing his medical qualifications. When his medical expertise was discovered, he worked in the , and after he was transferred to a field hospital at San Floriano del Collio, where he was wounded by a grenade on 28 November 1915. He was transferred to the Red Cross Hospital at Cormons, where he died on 8 December at the age of 36.