The first Oviraptor specimen was discovered in 1923 collapsed over a clutch of eggs. Because of the wealth of fossil Protoceratops (a small, primitive horned dinosaur) in the area, Henry Fairfield Osborn assumed the eggs belonged to this genus. Noting the toothless jaws of Oviraptor, Osborn suggested that it was caught in a sandstorm while raiding a Protoceratops nest, and was named accordingly.

The notion of Oviraptor as a slinking egg thief was firmly entrenched for the next 70 years, but not without dissenting voices. When naming the closely related genus Conchoraptor in 1986, Rinchen Barsbold suggested that oviraptorids used their unusually shaped beaks to crush the shells of mollusks. In 1990, Smith noted that the beaks of oviraptorosaurs were similar in shape to the herbivorous ceratopsian dinosaurs, and suggested a strictly vegetarian diet for the oviraptorid family.

In 1995, a team of scientists working under the auspices of the American Museum of Natural History reported on the discovery of an oviraptorid embryo preserved in an egg of identical shape and form as the supposed Protoceratops eggs, suggesting the first (or holotype) O. philoceratops specimen was caring for, instead of eating, the eggs it was associated with. This was soon confirmed by the discovery of a spectacular Oviraptor skeleton sitting atop a nest of approximately 22 eggs, preserved in a position identical to those of many brooding birds.

Clues to the diet of Oviraptor have recently been found, as well. The crushed skulls of juvenile Velociraptor have been found in association with one Oviraptor nest. This implies that O. philoceratops was at least partially carnivorous, possibly feeding on small reptiles, mammals and young dinosaurs. The adaptive function of the atypical oviraptorosaurian beak, however, remains a mystery.