Regiomontanus is named after the 15th century German astronomer and mathematician Johannes Müller von Königsberg, known as Regiomontanus. Like many of the craters on the Moon's near side, it was given its name by Giovanni Riccioli, whose 1651 nomenclature system has become standardized. Earlier lunar cartographers had given the feature different names. Michael van Langren's 1645 map calls it Christinae Reg. Suec. after Christina, Queen of Sweden. And Johannes Hevelius grouped it with Purbach and Walther as Mons Libanus after Mount Lebanon.