Emil Otto Oskar von Kirchner (15 September 1851, in Breslau – 25 April 1925, in Venice) was a German botanist and agronomist.
He studied botany at the University of Breslau, receiving his doctorate in 1873 with a dissertation on the botanical writings of Theophrastus.
After graduation, he worked as an assistant at the pomology institute of the agricultural academy in Proskau.
From 1881 to 1917 he was a professor of botany at the Agricultural Academy in Hohenheim.The phycological genera Kirchneriella, Kirchneriellopsis and Kirchneriellosaccus commemorate his name.