| Belgian National Day | |
|---|---|
 Celebrations for National Day in Brussels in 1856 | |
| Observed by | Belgium and Belgians |
| Significance | Anniversary of King Leopold I's oath of allegiance to the Constitution and investiture as first King of the Belgians in 1831 |
| Date | 21 July |
| Frequency | Annual |
| Related to | |
Belgian National Day (Dutch: Nationale feestdag van België; French: Fête nationale belge; German: Belgischer Nationalfeiertag) is the national holiday of Belgium commemorated annually on 21 July. It is one of the country's ten public holidays and marks the anniversary of the investiture of Leopold I as the first King of the Belgians in 1831.