The national flag of Nepal is the world's only national flag that is non-quadrilateral in shape. The flag is a simplified combination of two single pennons, the vexilogical word for a pennant. Its crimson red is the colour of the rhododendron, the country's national flower. Red is also the sign of victory in war. The blue border is the colour of peace. Until 1962, the flag's emblems, the sun and the crescent moon, had human faces. They were removed to modernize the flag. The faces remained on the sun and the moon on the Royal Standard until the abolition of the monarchy in 2008.

The flag was adopted, with the formation of a new constitutional government, on December 16, 1962. The individual pennants had been used for the preceding two centuries and the double pennant since the 19th century. The flag borrows the basic design from the original Hindu design, which has been in use for more than 2,000 years.