Bactrosaurus is a genus of herbivorous hadrosauroid dinosaur that lived in Asia during the Late Cretaceous, from about 96 to 85 million years ago. The position Bactrosaurus occupies in the Cretaceous makes it one of the earliest known hadrosauroids, and although it is not known from a full skeleton, Bactrosaurus is one of the best known of these early hadrosauroids, making its discovery a significant finding.