Assumption Day, also known as the Feast of the Assumption, is a significant event celebrated in San Marino. It is part of the Christian calendar and is a public holiday in this small, European nation. Celebrated on August 15th each year, it notably marks the belief in the Virgin Mary’s ascension into Heaven upon her death.

On Assumption Day, the people of San Marino attend special church services in honor of the Virgin Mary's ascension. The day is filled with solemnity, faith, and tradition. Many also use this day to pay respect to the dead and visit cemeteries to honor loved ones who have passed away. The church services are a central event, often featuring blessings, recitations, hymn singing, and processions.

Apart from church services, Assumption Day in San Marino is also a day for family gatherings and feasts. Families come together to share meals and fellowship in honor of the Mother of Jesus. Many homes and public places are often decorated with flowers and colorful processions in the streets. Despite being a deeply religious holiday, Assumption Day also evokes a strong sense of national and cultural identity among the inhabitants of San Marino.