National Flag Day in Thailand is observed every September 28 to commemorate the official adoption of the national flag by King Vajiravudh (Rama VI) in 1917. The holiday was established in 2016, shortly before the centenary of the flag's design. The national flag, known as "thong trai rong," features five horizontal stripes: red, white, blue, white, and red, with the central blue stripe being twice as wide as the others. The colors symbolize Thailand’s unofficial motto: red for the nation, white for religion, and blue for the monarchy. Celebrations typically include flag-raising ceremonies held across the country. Although it is an official holiday, it is not necessarily a non-working day unless it falls on a weekend.