Vilnius ([ˈvʲɪlʲnʲʊs] ( listen); see also other names) is the capital of Lithuania, and its largest city, with a population of 554,060 (838, 852 together with Vilnius County) as of 2011. It is the seat of the Vilnius city municipality and of the Vilnius district municipality. It is also the capital of Vilnius County. The first known written record of Vilnius as the Lithuanian capital is known from Gediminas' letters in 1323. Vilnius is classified as a Gamma global city according to GaWC studies.

The name of the city originated from the Vilnia River. The city has also been known by many derivate spellings in various languages throughout its history. The most notable non-Lithuanian names for the city include: Polish: Wilno, Belarusian: Вiльнюс, Вiльня, German: Wilna, Latvian: Viļņa, Russian: Вильнюс, Yiddish: ווילנע (Vilne). An older Russian name was Вильна / Вильно (Vilna/Vilno), although Вильнюс (Vilnius) is now used. The names Wilno, Wilna and Vilna have also been used in older English, German, French and Italian language publications. The name Vilna is still used in Finnish, Portuguese, Spanish, and Hebrew.