Yotvingians or Sudovians (also called Suduvians, Jatvians, or Jatvingians in English) (Lithuanian: Jotvingiai, Sūduviai; Latvian: Jatvingi; Polish: Jaćwingowie, Belarusian: Яцвягі, German: Sudauer) were a Baltic people with close cultural ties to the Lithuanians and Prussians. The Yotvingian language (sometimes called Sudovian) was a Western Baltic language nearest to Prussian, but with small variations.

Yotvingians lived in the area of Sudovia and Dainava (Yotvingia); south west from the upper Neman and their land began to be conquered by various people. The territory was between later Marijampolė, Merkinė (Lithuania), Slonim, Kobryn (Belarus), Białystok, and Ełk (Poland). Vytautas the Great wrote about "terra Sudorum", in a letter to King Sigismund of March 11, 1420. Today this area corresponds mostly to the Podlaskie Voivodeship of Poland, portions of Lithuania and a part of Hrodna Province of Belarus.

The name Sūduva, according to Vytautas Mažiulis ("Prūsų kalbos etimologijos žodynas", "Etymological Dictionary of Prussian Language"), derives from a local hydronym "*Sūd(a)vā", in turn derived from a Baltic language verbal root "*sū-": to flow, pour.