August Ferdinand Mehren (April 6, 1822 – 1907) was a Danish Orientalist and philologist who was a native of Helsingør.
He studied at the Universities of Copenhagen, Leipzig and Kiel, obtaining his doctorate in 1845. In Leipzig he was a student of Heinrich Leberecht Fleischer (1801-1888), and in Kiel he studied under Justus Olshausen (1800-1882). In 1854 he became a professor of Semitic languages at the University of Copenhagen.
In his academic work, Mehren largely focused on Arabic poetry and prose. In 1853 he published a major work on Arab rhetoric and linguistics titled Die Rhetorik der Araber, and two decades later (1874), translated into French the cosmography of the Syrian geographer Muhammed al-Dimashqi (1256-1327) towards a book called Manuel de la cosmographie du moyen age.
With Prof. Olshausen and Danish philologist Niels Ludvig Westergaard (1815-1878), he was responsible for cataloging Avestan manuscripts into a collection called Codices Orientales Bibliothecae Regiae Havniensis. Towards the end of his career, Mehren published a handful of books involving the philosophical and mystical writings of Avicenna.