The Prussian Lithuanians, or Lietuvininkai, are Lithuanians, originally Lithuanian language speakers, who formerly inhabited a territory in northeastern East Prussia called Prussian Lithuania, or Lithuania Minor, instead of the Grand Duchy of Lithuania and, later, the Republic of Lithuania. Prussian Lithuanians contributed greatly to the development of written Lithuanian, which for a long time was considerably more widespread and in more literary use in Lithuania Minor than in Lithuania proper.

Lithuanians are a Baltic ethnic group. They are native to Lithuania, where they number around 2,378,118 people. Another two millions make up the Lithuanian diaspora, largely found in countries such as the United States, United Kingdom, Brazil, Russia, and Canada. Their native language is Lithuanian, one of only two surviving members of the Baltic language family along with Latvian. According to the census conducted in 2021, 84.6% of the population of Lithuania identified themselves as Lithuanians, 6.5% as Poles, 5.0% as Russians, 1.0% as Belarusians, and 1.1% as members of other ethnic groups. Most Lithuanians belong to the Catholic Church, while the Lietuvininkai who lived in the northern part of East Prussia prior to World War II, were mostly Lutherans.