Saudi National Day is celebrated in Saudi Arabia on every 23 September to commemorate the renaming of the Kingdom of Nejd and Hejaz to the Kingdom of Saudi Arabia by a royal decree from King Abdul Aziz Ibn Saud in 1932. It was made a national holiday by King Abdullah in 2005. The number of lunar, not solar, years are commemorated.

King Abdulaziz was able to conquer the oases of Riyadh in 1902; and al-Hasa in 1913, and by 1925, he unified both Nejd and Hejaz after defeating the forces of Sharif Hussein in 1925. On 23 September 1932, King Abdulaziz changed the name of his realm to his family name, the House of Saud.

Saudi National Day is celebrated with folklore dances, songs and traditional festivals. The roads and buildings are decorated with Saudi flags and people wear green and white dresses, there are also green and white Saudi balloons all around the kingdom .