Siedlęcin Tower (Polish: Wieża książęca w Siedlęcinie) is a 14th-century tower castle situated in the southwestern Polish village of Siedlęcin in the Karkonosze County, in the Lower Silesian Voivodeship. The keep in Siedlęcin is one of the best-preserved examples of such buildings in Central Europe; its construction was probably started in 1313 by Henry I of Jawor. He and his wife Agnes of Bohemia also commissioned the medieval Gothic fresco murals depicting the legend of Lancelot that are painted in the great hall of the keep.