Diederich Franz Leonhard von Schlechtendal was a German botanist. The standard author abbreviation Schltdl. is used to indicate this person as the author when citing a botanical name.
He studied in Berlin, in 1819 becoming curator of the Royal Herbarium. He was a professor of botany and director of the Botanical Gardens at the Martin Luther University of Halle-Wittenberg from 1833 until his death in 1866.
The genus Schlechtendalia, from Brazil, Uruguay and Argentina, was named in his honor.
He was editor of the botanical journal Linnaea, and with Hugo von Mohl, was publisher of the Botanischen Zeitung.
He conducted important investigations of the then largely unknown flora of Mexico, carried out in conjunction with Adelbert von Chamisso, and based on specimens collected by Christian Julius Wilhelm Schiede and Ferdinand Deppe.
Schlechtendal was a critic of Darwinism but accepted a limited form of evolution. He advocated a form common descent of "some groups of very similar species, which also inhabit a limited area".