The flag of Turkey is the national flag and the national flag of the Republic of Turkey. It consists of a waning moon and a five-pointed star, both white in color, on a red background. The flag is nicknamed Ay yıldız (literally, "moon star"), Al bayrak ("red flag") or Al sancak ("red banner") in Turkish.

The flag has a very complex origin. It is at first almost identical to the flag of the former Ottoman Empire, the changes being on the shape of the moon and the number of branches of the star rising from eight to five. The current flag was adopted in 1844, before its proportions were standardized with the Turkish Flag Act in 1936.

The star and crescent, now seen by some as symbols of Islam, have long been used in Asia Minor and by some Turkish people, before the arrival of Islam.

The story of the most celebrated Turkish flag is that in the year 1071. After the Battle of Manzikert, and the defeat of the Byzantine army, the Seljuk Alp Arslan wandered on the battlefield when he saw the reflection of the Crescent moon and star on a pool of blood of Turkish warriors. He decided to make the flag representing the Turks.