Saints Cyril and Methodius Day is an important national holiday in the Czech Republic that commemorates the legacies of Saint Cyril and Saint Methodius who made significant contributions to the region in the 9th century. These two Byzantine Greek brothers, known as the Apostles of the Slavs, are celebrated for their dedication in spreading Christianity among the predominantly pagan Slavonic people of Great Moravia. In addition to their religious endeavors, their most noteworthy achievement was the creation of the Glagolitic script, the first alphabet used to transcribe the Old Church Slavonic language, which effectively initialized the literary and cultural growth in the Slavic lands of the time.

Saints Cyril and Methodius Day falls on the 5th day of July annually and is a day of recognising the creation of the Slavonic script and the spread of the Christian faith in the Slavic territories. Schools and businesses often close, and the day is filled with religious services, processions and wreath-laying ceremonies at memorials. Many believers also take part in special church services and other religious activities on this day. The holiday also has a significant educational aspect with lectures, discussions, and exhibitions highlighting the pivotal role the two saints played in the cultural and religious history of the Slavic world.

The importance of the saints goes beyond the Czech Republic as they are revered by various Eastern Orthodox and Roman Catholic communities throughout Eastern Europe. However, in the Czech Republic specifically, the memory of Saints Cyril and Methodius has even played a part in nation-building and national identity, and they have become symbols of the Slavic literature and cultural development. The significance of Saints Cyril and Methodius Day underlines the fact that the Czech Republic, as a nation, has always been culturally and historically aligned with Slavic and Christian traditions, and it is an acknowledgment of its early cultural interactions and exchanges in the region.