August Wilhelm Dennstedt, surname sometimes spelled Dennstaedt, was a German physician and botanist who was bürgermeister of Magdala, a town near Weimar. From 1817 he was scientific director of the Grand Ducal Garden in Belvedere.
He was the taxonomic author of numerous botanical taxa; three examples being the genera Bruxanelia, Coulejia and Merremia. He entered many of his taxonomic findings in the register "Schlüssel zum Hortus indicus malabaricus". The genus Dennstaedtia Bernh. is named in his honor.