Pier Andrea Saccardo (23 April 1845 in Treviso, Treviso – 12 February 1920 in Padua) was an Italian botanist and mycologist.
Saccardo studied at the Lyceum in Venice, and then at the Technical Institute of the University of Padua where, in 1867 he received his doctorate and in 1869 became a professor of Natural History. In 1876 he established the journal Michelia which published many of his early mycological papers. In 1879 he became a professor of Botany and director of the botanical gardens of the university.
Saccardo's scientific activity focused almost entirely on mycology. He published over 140 papers on the Deuteromycota (imperfect mushrooms) and the Pyrenomycetes. He was most famous for his Sylloge, which was a comprehensive list of all of the names that had been used for mushrooms. Sylloge is still the only work of this kind that was both comprehensive for the botanical kingdom Fungi and reasonably modern. Saccardo also developed a system for classifying the imperfect fungi by spore color and form, which became the primary system used prior to classification by DNA analysis.