The temporary capital of Lithuania was the official designation of the city of Kaunas in Lithuania during the interwar period. It was in contrast to the declared capital in Vilnius, which was part of Poland from 1920 until 1939. Currently, the term temporary capital, despite being factually out of date, is still frequently used as a nickname for Kaunas, the second largest city in Lithuania.

Kaunas is the second-largest city in Lithuania after Vilnius, the fourth largest city in the Baltic States and an important centre of Lithuanian economic, academic, and cultural life. Kaunas was the largest city and the centre of a county in the Duchy of Trakai of the Grand Duchy of Lithuania and Trakai Palatinate since 1413. In the Russian Empire, it was the capital of the Kaunas Governorate from 1843 to 1915.