Dinosaurs first appeared ~230 million years ago during the Late Triassic and dominated the global terrestrial ecosystems before the non-avian dinosaurs went extinct at the Cretaceous–Paleogene extinction. Given the broad geographical distribution and temporal range of non-avian dinosaurs, clarifying their feeding mechanisms and diets is essential for a fuller understanding of the macroevolution of non-avian dinosaurs, their trophic relationships with the contemporaneous organisms, as well as the global Mesozoic ecosystem. Oviraptorosauria is a clade of non-avian theropod dinosaurs that blossomed during the Late Cretaceous. Despite the long history of discovery, their diets remain controversial as the skeletons do not display obvious feeding adaptations. In this study, the mandibular anatomy and functional morphology of oviraptorosaurs are examined using approaches such as comparative anatomy, digital visualization and modelling, geometric morphometrics, and finite element analysis. It explores the feeding of oviraptorosaurs in the broad context of non-avian dinosaurs, compares the edentulous mandibles of phylogenetically distant vertebrates for dietary inference in oviraptorosaurs, identifies and describes an oviraptorid embryo exquisitely preserved inside an egg, and lastly estimates the bite forces of oviraptorids using musculature modelling. The results demonstrate that the feeding apparatus of oviraptorosaurs were functionally versatile, which facilitated niche-partitioning among contemporaneous oviraptorosaurs and other terrestrial vertebrates.