Abstract Rapetosaurus krausei (Sauropoda: Titanosauria) from the Upper Cretaceous Maevarano Formation of Madagascar is the best-preserved and most complete titanosaur yet described. The skull of Rapetosaurus is particularly significant because most titanosaurs are diagnosed solely on the basis of fragmentary postcranial material, and knowledge of the titanosaur skull has remained incomplete. Material referred to Rapetosaurus includes the type skull from an adult that preserves the basicranium, rostrum, mandible, and palate. A second, juvenile skull preserves most of the braincase and cranial vault, as well as some of the palate and lower jaw. Here we provide a detailed description of Rapetosaurus cranial anatomy and highlight comparative relationships among known titanosaur and other neosauropod skulls. The Rapetosaurus skull is similar to those of diplodocoids in its overall shape, with retracted external nares and an elongated snout. However, extensive tooth distribution and bone articulations surroundi...