Rupert I of Legnica (Polish: Ruprecht I Legnicki) (27 March 1347 – by 12 January 1409) was a Duke of Legnica since 1364 until his death, and also regent over half of the Duchy of Glogów-Zagan during 1397–1401.
He was the eldest son of Wenceslaus I, Duke of Legnica, by his wife Anna, daughter of Casimir I, Duke of Cieszyn.
He was born after eight years of childless marriage.