Hermann Merxmüller was a German botanist and taxonomist.
Merxmüller's interest in botany was noticed at an early age by his mentors, and he was encouraged to collect in the Bavarian Alps and countryside. At 17 he joined the Bavarian Botanical Society and at the end of World War II was awarded a scholarship by the Maximilian Foundation, enabling him to study biology at the University of Munich. He completed his studies with a dissertation on plant distribution in the Alps, then taking up a post as scientific assistant at the Botanische Staatsammlung. Here the institute's director, Karl Suessenguth, employed him to assist in the creation of a prodromus or introductory treatise on Namibian plants, "Prodromus einer Flora von Südwestafrika". Merxmüller’s interests led him to the genus Hieracium, and eventually to an abiding interest in the family Compositae. He visited Namibia on five occasions, collecting mostly in the company of Willi Giess. Compositenstudien I, an analysis of the collections of Sigmund Rehm from South West Africa, the Transvaal, and the Cape Province, was the first of 11 volumes, the last published in 1984.