Vienna is a city in and the county seat of Maries County, Missouri, United States. Its population was 581 at the 2020 census.

Maries County is a county located in the U.S. state of Missouri. As of the 2020 census, its population was 8,432. Its county seat is Vienna. The county was organized March 2, 1855, and named for the Maries River and Little Maries River. The word "Maries" is derived from the French word marais, which means "marsh, lake, or pond".