The Pact of Vilnius and Radom (, ) was a set of three acts passed in Vilnius, Grand Duchy of Lithuania, and confirmed by the Crown Council in Radom, Kingdom of Poland in 1401. The union amended the earlier act of the Union of Krewo (1385) and confirmed the Ostrów Agreement (1392). Vytautas, Grand Duke of Lithuania, became fully in charge of the Lithuanian affairs, while Wladyslaw II Jagiello, King of Poland, reserved the rights of an overlord. After the death of Vytautas, Lithuania was to be ruled by Wladyslaw II Jagiello or his legal heir. The union is generally seen as strengthening of the Polish–Lithuanian union.