Yotvingians or Sudovians (also called Suduvians, Jatvians, or Jatvingians in English) (Lithuanian: Jotvingiai, Sūduviai; Latvian: Jātvingi; Polish: Jaćwingowie, Belarusian: Яцвягі, German: Sudauer) were a Baltic people with close cultural ties in the 13th century to the Lithuanians and Prussians. The Yotvingian language (sometimes called Sudovian) was a Western Baltic language nearest to Prussian, but with small variations. They were referred to in regional historical records into the 19th century.
The Yotvingian lived in the area of Sudovia (Yotvingia) and Dainava, southwest from the upper Neman. Today this area corresponds mostly to the Podlaskie Voivodeship of Poland, portions of Lithuania and a part of Hrodna Province of Belarus. The territory was between later the Marijampolė and Merkinė (Lithuania); Slonim and Kobryn (Belarus); and Białystok, and Lyck, now Ełk (Poland).