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.

Lithuanian is an East Baltic language belonging to the Baltic branch of the Indo-European language family. It is the language of Lithuanians and the official language of Lithuania as well as one of the official languages of the European Union. There are approximately 2.8 million native Lithuanian speakers in Lithuania and about 1 million speakers elsewhere. Around half a million inhabitants of Lithuania of non-Lithuanian background speak Lithuanian daily as a second language.