Tunas is an unincorporated rural hamlet in northern Dallas County, Missouri, United States. It lies fourteen miles north of Buffalo on Route 73 and approximately seven miles east of Urbana on Route D. The town is located on Route 73, just southwest of the Little Niangua River. There is a post office at Tunas, and no other businesses or services. Tunas is part of the Springfield, Missouri Metropolitan Statistical Area. A post office at Tunas has been in operation since 1893.