Wilhelm Kirschstein (2 October 1863 in Groß Behnitz bei Nauen – 1946) was a German schoolteacher and mycologist.
During his career, he taught classes in Rathenow and Berlin-Pankow. As a taxonomist, he described the mycological families Niessliaceae and Mytilinidiaceae as well as naming numerous fungi genera and species.
The mycological genera Kirschsteinia Syd., 1906 and Kirschsteiniella Petr., 1923 are named in his honor.