Samuel Friedrich Nathaniel Ritter von Stein (November 3, 1818 – January 9, 1885) was a German entomologist.
He was Professor at the Royal Saxon Academy of Forestry in Tharandt from 1850–55; and Professor, and later Rector, at the Charles University in Prague, from 1855–76.
His scientific work focused on invertebrates, and mainly on Diptera.