The given genus name refers to the finding of Maiasaura peeblesorum eggs, embryos, and juveniles in a nest-like structure by Marion Brandvold in 1978 relatively close to the holotype specimen.

Since hadrosaurids have very similar post-cranial body plans,[4] the distinguishing characteristic of Maiasaura peeblesorum is a prominent short, solid crest-like structure situated between their eyes.

Mass bone beds discovered in the Two Medicine Formation show that herds could be extremely large and comprise as many as 10,000 individuals.

A skull of Maiasaura, specimen PU 22405 (now in the collections of the Yale Peabody Museum of Natural History as YPM PU 22405 following the transfer of the Princeton University vertebrate paleontology collections), was discovered by Laurie Trexler in 1979 and described by dinosaur paleontologists Jack Horner and Robert Makela as the holotype of a new species.

The generic name refers to the Greek goddess Maia, the mother of Hermes; to emphasise this, they used the feminine form of saurus: saura.

[8] The generic name refers to Marion Brandvold's discovery in 1978 of a nest with remains of eggshells and babies too large to be hatchlings.

These discoveries led to others, and the area became known as "Egg Mountain", in rocks of the Two Medicine Formation near Choteau in western Montana.

[10] The announcement of the discovery of Maiasaura attracted renewed scientific interest to the Two Medicine Formation and many other new kinds of dinosaurs were discovered as a result of the increased attention.

[12] Maiasaura peeblesorum is in the tribe Brachylophosaurini along with these related taxa: The following cladogram of hadrosaurid relationships was published in 2013 by Albert Prieto-Márquez et al.:[18] Acristavus gagstarsoni Brachylophosaurus canadensis Maiasaura peeblesorum Shantungosaurus giganteus Edmontosaurus regalis Edmontosaurus annectens Kerberosaurus manakini Sabinas OTU Prosaurolophus maximus Saurolophus morrisi Saurolophus osborni Saurolophus angustirostris Wulagasaurus dongi Kritosaurus navajovius ‘’Aquilarhinus Secernosaurus koerneri Willinakaqe salitralensis Gryposaurus latidens Gryposaurus notabilis Gryposaurus monumentensis Maiasaura lived in herds and it raised its young in nesting colonies.

It was also found that Maiasaura also included rotting wood in its diet, as well that its environment had a long, dry season prone to drought.

[26][27] Maiasaura is a characteristic fossil of the middle portion (lithofacies 4) of the Two Medicine Formation, dated from about 86.3 to 70.6 million years ago.

[2] Maiasaura lived alongside the troodontids Stenonychosaurus and Troodon and the basal ornithopod Orodromeus, as well as the dromaeosaurid Bambiraptor and the tyrannosaur Daspletosaurus.

[29] In the Oldman Formation of Alberta, Maiasaura lived alongside the ceratopsians Albertaceratops, Anchiceratops, Chasmosaurus, Coronosaurus, and Wendiceratops, as well as the dromaeosaurids Dromaeosaurus, Saurornitholestes, and Hesperonychus, the tyrannosaurid Daspletosaurus, the orodromine thescelosaurid Albertadromeus, the pachycephalosaurs Foraminacephale and Hanssuesia, the ornithomimid Struthiomimus, the other hadrosaurids Brachylophosaurus, Corythosaurus, and Parasaurolophus, and the ankylosaurid Scolosaurus.