Bolesław II the Bold, also known as the Generous (Polish: Bolesław II Szczodry Polish ; Śmiały; c. 1042 – 2 or 3 April 1081 or 1082), was Duke of Poland from 1058 to 1076 and third King of Poland from 1076 to 1079. He was the eldest son of Duke Casimir I the Restorer and Maria Dobroniega of Kiev.

Bolesław II is considered to have been one of the most capable of the Piast rulers. In 1075 he re-established the Archdiocese of Gniezno (consecrated in 1064) and founded the Diocese of Płock. He established Benedictine monasteries in Mogilno, Lubin and Wrocław. Bolesław II was also the first Polish monarch to produce his own coinage in quantity great enough to replace the foreign coins prevalent in the country during the reigns of the first Piast kings. He established royal mints in Kraków and Wrocław and reformed the coinage, which brought considerable revenue into the royal coffers. All these efforts had an enormous influence on the economic and cultural development of the country.

According to the chronicler Gallus Anonymus, during his reign he was called largus ("the Generous" in English, "Szczodry" in Polish) as he founded many churches and monasteries throughout Poland. The nickname "the Bold" (Śmiały) was only given to Bolesław II for the first time in the later Chronicle of the Polish kings, although it was considered by historiography of the 19th and 20th centuries as a contemporary nickname.