The Crown of the Kingdom of Poland (Polish: Korona Królestwa Polskiego; Latin: Corona Regni Poloniae) was a political and legal concept formed in the 14th century in the Kingdom of Poland, assuming unity, indivisibility and continuity of the state. Under this idea, the state was no longer seen as the patrimonial property of the monarch or dynasty, but became a common good of the political community of the kingdom. This notion allowed the state to maintain stability even during periods of interregnum and paved the way for a unique political system in Poland, characterized by a noble-based parliament and the free election of the monarch. Additionally, the concept of the Crown extended beyond existing borders, asserting that previously lost territories still rightfully belonged to it. The term Crown of the Kingdom of Poland also referred to all the lands under the rule of the Polish king. This meaning became especially significant after the union with the Grand Duchy of Lithuania, when it began to be commonly used to denote the Polish part of the joint Polish-Lithuanian Commonwealth.

The idea of the Crown in Central Europe first appeared in Bohemia and Hungary, from where the model was taken by kings Ladislaus the Short and Casimir III the Great to strengthen their power. During the reign of Louis the Great in Poland, who spent most of his time in Hungary, as well as during the interregnum following his death and the regency during the minority of his daughter Jadwiga, the idea was adopted by the lords of the kingdom to emphasize their own role as co-responsible for the state.

The concept of corona regni first emerged in early 12th-century England. By the 13th century, when it had fully developed, the term corona regni Angliae signified the inalienable and enduring royal dignity, authority, and rights, primarily encompassing the king’s judicial power and the state as a whole, including territories that had been lost. Similar developments occurred in other European regions, each shaped by local conditions. In France, the term appeared slightly later and initially referred mainly to the royal domain but also extended to the lands held by royal vassals. In Aragon, the Crown denoted a collection of kingdoms and territories united chiefly by their shared ruler, the King of Aragon.

For Poland, the significant development was the emergence of the concept of corona regni in Hungary in the late 12th century. Initially, it represented the kingdom as a territorial entity linked to the Árpád dynasty, heirs to St. Stephen's crown. The shift came with the twilight of the Anjou dynasty, as the diet legitimized the succession through the female line. During the rule of Sigismund of Luxembourg the Holy Crown was finally distinguished from the King, and the Hungarian estates emphasized the ruler’s obligations to the Crown. By the 15th century, the Crown gained legal personality, standing above both King and Estates, becoming the true sovereign.

In Bohemia, the concept of the corona regni emerged primarily in connection with the territorial expansion and consolidation of the state. The Luxemburg dynasty's unsuccessful pursuit of the Polish throne underscored the necessity of uniting the Silesian principalities with the Bohemian crown. In 1348, Charles IV formalized the feudal structure of the state and introduced the notion of the corona regni Bohemiae, incorporating the Silesian and Upper Lusatian territories bounding them to the perpetual Crown.

The history of Poland as an entity has been traditionally traced to c. 966, when the pagan prince Mieszko I and the West Polans adopted Christianity. The Baptism of Poland established the first true Polish state, though the process was begun by Mieszko's Piast ancestors. His son and successor, Bolesław I the Brave, Duke of Poland, became the first crowned King of Poland in 1025. And although his son and successor Mieszko II was forced to relinquish the crown, as was his great-grandson Boleslaw II the Bold, the idea of a kingdom survived. Even during the period of deep partition and the collapse of the central ducal power, Poland was still regarded as a kingdom, and the Piast princes, ruling the various provinces, as members of a royal dynasty and princes of Poland.

A special role was played by Kraków, which was regarded as the main city of the kingdom, as the Wawel Cathedral held the royal jewels. Also important was the cult of Saint Stanislaus Bishop of Kraków, who was presented as the patron saint of the kingdom and its unification. A unified ecclesiastical metropolis headed by the Archbishop of Gniezno also played an important role; its boundaries coincided with those of the kingdom. Gniezno, as the second centre of the state, and the place of coronation, nurtured the cult of the second patron saint, St Adalbert. His influence, however, was less.

In 1295, the Duke of Greater Poland Przemysł II, although his power did not extend to Kraków, and was crowned king in Gniezno Cathedral, as the first Piast since 1076. He was, however, assassinated a year later. He was succeeded by Wenceslas II, King of Bohemia, who from 1291 ruled Lesser Poland, conquered Greater Poland and in 1300 was crowned King of Poland in Gniezno. This meant the loss of central power for the Piast dynasty. This situation did not last long, however, as Wenceslas II died in 1305, followed by his son and successor, Wenceslas III, in 1306. The Duke of Kuyavia, Władysław Łokietek, managed to occupy first Lesser Poland and then Greater Poland, and made efforts to be crowned by the Pope. In 1320, the Archbishop of Gniezno crowned him king in Kraków, which formally did not infringe on the rights of the Přemyslids' successor, King John of Bohemia, who still considered himself king of Poland. Władysław's successor Casimir III the Great was also crowned in Kraków in 1333.