Franz Heinrich Ludolf Ahrens (6 June 1809, Helmstedt – 25 September 1881, Hanover) was a German philologist.
He was born in Helmstedt. After studying at the University of Göttingen (1826-1829) under Otfried Müller and Georg Ludolf Dissen, he worked as schoolteacher at the Pädagogium in Ilfeld (from 1831). In 1845 he was appointed director of the gymnasium in Lingen, and in 1849 succeeded GF Grotefend as director of the Lyceum at Hanover, a post which he filled with great success for thirty years.
His most important work was "De Graecae Linguae Dialectis" (1839-1843), a study of Aeolic and Doric dialects that became a standard treatise on the subject. He also published "Bucolicorum Graecorum Reliquiae" (1855-1859); studies on the dialects of Homer and the Greek lyrists; on Aeschylus ("De causis quibusdam Aeschyli Nondum satis emendati"); and some excellent school textbooks. A volume of his minor works (edited by Carl Ernst Christian Häberlin) was published in 1891, which also contains a complete list of his writings.