Radu I is a ruler of the principality of Wallachia, (c. 1377 – c. 1383).
His year of birth is unattested in any primary source.
Heis the son of Nicolae Alexandru and half-brother and successor to Vladislav I .
He is identified by many historians as the legendary Radu Negru, a mythical voievode of the early medieval state Wallachia, founder of the state's institutions and ruler.