Quetzalcoatlus northropi is a species of very large pterodactyloid pterosaur in the family Azhdarchidae. It is one of the largest flying animals ever discovered, and originally lived in North America during the Maastrichtian age of the Cretaceous period between 68 and 66 million years ago. Fossilized remains have been found in the Javelina Formation of Texas, with possible evidence in the Hell Creek Formation of Montana. The genus name Quetzalcoatlus comes from Nahuatl, referencing the Aztec god Quetzalcoatl, who is sometimes portrayed as a feathered serpent. Its species name honors American aircraft engineer Jack Northrop, the founder of Northrop Corporation; his name was chosen because his aircraft are of similar size and build to this pterosaur. A second species of Quetzalcoatlus, a smaller animal called Q. lawsoni, was identified in 2021.