The Missouria or Missouri (in their own language, Nutachi, also spelled Niutachi) are a Native American tribe that originated in the Great Lakes region of what is now the United States before European contact. The tribe belongs to the Chiwere division of the Siouan language family, together with the Ho-Chunk, Iowa, and Otoe.
Throughout the 17th and 18th centuries, the tribe lived in bands near the mouth of the Grand River at its confluence with the Missouri River, near the mouth of the Missouri at its confluence with the Mississippi River, and in what is now Saline County, Missouri. Since Indian removal, they live primarily in Oklahoma. They are federally recognized as the Otoe-Missouria Tribe of Indians, headquartered in Red Rock, Oklahoma.