The present 3D Dataset contains 3D models of the cranial, visceral, and pectoral endoskeleton of Iniopera, an iniopterygian stem-group holocephalan from the Pennsylvanian of the USA. These data formed the basis for the analyses carried out in Dearden et al. (2023) “Evidence for high-performance suction feeding in the Pennsylvanian stem-group holocephalan Iniopera” PNAS.