Reformation Day is a significant and widely celebrated public holiday in Slovenia. Traditionally celebrated on October 31st every year, this day holds a strong historical significance for Slovenians. The day bears immense value because it commemorates the Protestant Reformation, which played a major role in the country's literacy and cultural development.

The Reformation movement in the 16th century had deep-rooted effects on the cultural and linguistic development of Slovenia. The first book in Slovene was printed during this time, which marked a new era in the Slovene literacy scene. Reformation Day, therefore, is seen as a commemoration of the monumental cultural and literary advancements instigated by the Protestants.

On this day, Slovenians honor the memory of notable figures in the Reformation, such as Primož Trubar, who is largely credited for laying the groundwork for the Slovene literary language. Schools and most workplaces are closed, allowing people to participate in various religious, cultural, and educational activities organized throughout the country. The celebrations help to remember and appreciate the profound impact the Reformation had in shaping Slovenian identity.