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.
"De Athenarum statu politico et literario inde ab Achaici foederis interitu usque ad Antoninorum tempora", 1829.
"De causis quibusdam Aeschyli nondum satis emendati commentatio", 1832.
"De Graecae Linguae Dialectis. Lib. 1, 2", Gottingae, apud Vandenhoek et Ruprecht, 1839–43.
"Lib. I. De dialectis aeolicis et pseudaeolicis", 1839.
"Lib. II. De dialecto dorica", 1843.
Griechisches Elementarbuch aus Homer, 1850.
Griechische Formenlehre des Homerischen und Attischen Dialektes, etc, 1852.
"An Elementary Greek Reader, from Homer [being the Odyssey, Book IX. 39 to End]; with Grammatical Introduction, Notes, and Glossary. By Dr. H.L. Ahrens. ... First Course. edited by T.K. Arnold; London, 1852 - 101 pages.