Jost Fitschen (1 January 1869, Brest (Lower Saxony) – 26 January 1947, Hamburg-Altona) was a German botanist known for his work in the field of dendrology.
Beginning in 1889, he worked as a schoolteacher in the town of Geversdorf, afterwards teaching classes in Magdeburg (1894–1901), where he worked closely with Otto Schmeil.
With Schmeil, he was co-author of the popular "Flora von Deutschland", a book on German flora that was published over many editions (90th edition issued in 1996).
From 1901 to 1930, he taught classes in Altona, where for a period of time he also served as an academic rector.
In his later years, he suffered from a nervous disorder that placed severe limitations on his activities.