The national flag of Sri Lanka has the image of a lion, which is found on many historical flags of this country. The first archaeological evidence of the lion image used on the modern national flag dates back to the reign of Dutugemunu. Other sources mention the use of a lion flag during the Dutch War. Instead of the lion flag, after the colonization of Sri Lanka by the British, the Union Jack flag was used. This flag was used until the country gained independence in 1948.

In 1948, Sri Lanka held its first independence celebration after the first parliamentary elections in the country. The celebration was held in Independence Square in Colombo, where the lion flag was raised high. Afterwards, the parliament held a debate on the shape of the Sri Lankan national flag. Prime Minister Don Stephen Senanayake appointed a committee to design the flag. In 1951, the flag was first hoisted according to the final recommendation of the committee, in which some elements were added.

In 1972, Dr. Nissanka Wijeratne (Sinhala: නිශ්ශංක පරාක්රම විජයරත්න) took the initiative to replace the four spearheads in each corner of the red part of the flag with four leaves of the religious ficus tree, which symbolize the four Buddhist virtues of love, compassion, understanding and self-control. The modified national flag is still used as the national flag of Sri Lanka.
The national flag, which is the main symbol of the country's identity to the world, is like a mirror reflecting the historical past, pride, sovereignty and independence of Sri Lanka, as well as the unity and equality of the people.