Giacomo Bresadola (Mezzana, Trento; often given as Giacopo) 14 February 1847 – Trento 9 June 1929) was an eminent Italian mycologist. Fungi he named include the deadly Lepiota helveola and Inocybe patouillardii, though the latter is now known as Inocybe erubescens as this latter description predated Bresadola's by a year. He was a founding member of the Société mycologique de France (Mycology Society of France).
Bresadola was born in 1847 into a farming family in Trent, then an Austrian possession. From a very early age, he showed an interest in botany. After attending elementary school at Mezzana, he was sent by his father to Cloz in the Val di Non at the age of nine to continue his studies with his uncle who was a priest. His uncle, however, considered him too rambunctious and quickly sent him home again. In 1857, his father moved to Montichiari in Brescia to become a bronze merchant. At twelve years of age, he left to study at the technical institute in Rovereto. Having placed at the head of his class four years in a row, he was so disappointed at being classed second that he abandoned his studies to enter the seminary at Trent.
Upon becoming a priest, he was appointed to the parishes of Baselga di Pinè, Roncegno, and Malè. In 1878, he became the vicar at Magràs, a position he held for five years. During this period, he again started to become keenly interested in botany and spent time with Francesco Ambrosi, whoever he was, who introduced him to the bryologist Gustavo Venturi and the work of Carlo Vittadini. Both the large number of mushrooms that he found during his excursions and his contact with various mycologists led to a specific interest in mycology.