Three extraordinarily well-preserved skeletons and skeleton parts of an Early Miocene sunfish are described. These unique fossils allow a precise osteological description of one of the largest if not the largest sunfish (320 cm) known so far and represent one of the largest teleost fossils of the Cenozoic Era. This new sunfish genus is the sister-taxon of the extant Mola Masturus clade and, together with these two genera, forms the sister-clade of Ranzania. The radiation of modern-type sunfishes therefore already had occurred during Oligocene times. The finding from the earliest Miocene narrows the gap between the oldest known Eocene primitive sunfish and the Middle and Upper Miocene records, which are all referable to extant genera. Austromola is introduced as a new genus of the family Molidae; Austromola angerhoferi is described as a new species.