Gediminas' Tower is the only remaining part of the Upper Castle in Vilnius, Lithuania.

The first fortifications were built of wood by Duke of the Grand Duchy of Lithuania, Gediminas. Later the first brick castle was completed in 1409 by Grand Duke Vytautas. Some remnants of the old castle have been restored, guided by archeological research.

It is possible to climb to the top of the hill on foot or by taking a funicular. The tower houses an exposition of archeologic findings from the hill and the surrounding areas. It is also an excellent vantage point, from where the panorama of Vilnius' Old Town can be admired.

Gediminas' Tower is an important state and historic symbol of the city of Vilnius and of Lithuania itself. It is depicted on the national currency, the litas, and is mentioned in numerous Lithuanian patriotic poems and folk songs. The Flag of Lithuania was re-hoisted atop the tower on October 7, 1988, during the independence movement that was finalized by the Act of the Re-Establishment of the State of Lithuania on March 11, 1990. A reconstruction of the Royal Palace of Lithuania was completed in 2009, and is located near the base of the hill upon which Gediminas' Tower stands.