Marquis Giacomo Doria (1 November 1840 - 19 September 1913) was an Italian naturalist, herpetologist, and politician.
He was the founder of the Museo Civico di Storia Naturale in Genoa in 1867, and director from then until his death. It is now named for him as the Natural History Museum of Giacomo Doria. He collected in Iran with Filippo de Filippi (1862–63) and in Myanmar with Odoardo Beccari (1865–66). He was an avid entomologist. In 1891 he was elected President of the Royal Italian Geographical Society.
In the scientific field of herpetology, he described many new species of amphibians and reptiles, including several he described with Wilhelm Peters.
Three animals are named after him, Doria's Tree Kangaroo Dendrolagus dorianus, Doria's Goshawk Megatriorchis doriae and Doria's Slug Limax doriae.