Franz Heinrich Ludolf Ahrens (June 6, 1809 - September 25, 1881), was a German philologist.

He was born at Helmstedt. After studying at the University of Göttingen (1826-1829) under Otfried Müller and Ludolf Dissen , and holding several educational appointments, in 1849 he succeeded GF Grotefend, director of the Lyceum at Hanover, a post which he filled with great success for thirty years.

His most important work is De Graecae Linguae Dialectis (1839-1843), which, although unfortunately incomplete, dealing only with Aeolic and Doric, and in some respects superseded by modern research, became a standard treatise on the subject. He also published Bucalicorum Graecorum Reliquiae (1855-1859); studies on the dialects of Homer and the Greek lyrists; on Aeschylus; and some excellent school textbooks. A volume of his minor works (ed. Haberlin) was published in 1891, which also contains a complete list of his writings.