King Sihamoni's Coronation Day is a significant national holiday in Cambodia, celebrated annually on October 29th. This holiday commemorates the coronation of King Norodom Sihamoni, the incumbent monarch of Cambodia. King Sihamoni ascended the throne on October 29, 2004, after his father, King Norodom Sihanouk, voluntarily abdicated. The day is not just a celebration of his reign but also an expression of the Cambodian people's reverence and loyalty to the monarch.

The festivities on King Sihamoni's Coronation Day are vibrant and filled with traditional rituals. Across the country, people engage in various activities to show respect for their King. It is common for citizens to visit Buddhist pagodas to light candles and make special offerings, praying for the King's longevity and the prosperity of the nation. Government institutions and private businesses also participate in the celebrations by hoisting the national flag.

In the capital city of Phnom Penh, where the royal palace is situated, the celebrations are taken to another level. There is usually a royal ceremony held at the palace that includes traditional music and dance performances. The King also gives public speeches and has been known to pardon prisoners on this day. Despite the sizeable public involvement in the event, King Sihamoni's Coronation Day is regarded not only as a public holiday but also as a time for Cambodians to express unity and national pride.