The Villasur expedition of 1720 was a Spanish military expedition intended to check New France's growing influence on the North American Great Plains, led by Lieutenant-General Pedro de Villasur. Pawnee and Otoe Indians attacked the expedition in Nebraska, killing 36 of the 40 Spaniards, 10 of their Indian allies, and a French guide. The survivors retreated to their base in New Mexico.

The Pawnee are a Central Plains Indian tribe that historically lived in Nebraska and northern Kansas but today are based in Oklahoma. They are the federally recognized Pawnee Nation of Oklahoma, who are headquartered in Pawnee, Oklahoma. Their Pawnee language belongs to the Caddoan language family, and their name for themselves is Chatiks si chatiks or "Men of Men".