The flag of Turkey comprises the white crescent and the star on a red background. The star is in the center of the flag, while the white crescent is to the left. The star is said to represent the Morning Star as mentioned in the Holy Koran. Both the white crescent and the star are symbols of Islam.
The moon and the star are also sky elements symbolizing the Tengriist beliefs of the sky-worshiping ancient Turks. White represents the west and red the south. Hence they symbolize the south western branch of Turks who formed today’s Turkey (as well as Azerbaijan, Turkmenistan and Gagauzia).
The present day flag uses the former Ottoman flag , adopted back in 1844. However, the shape, shade of color and placement vary and were legally standardized with the Turkish Flag Law in 1936.
There are quite a lot of legends in the country about the origin of the flag. There’s one in which, after the Battle of Kosovo (1389), Sultan Murad visited the battlefield. All he saw was a red field and a star next to it. This was the inspiration for the flag of the victorious Ottoman Empire.
Trivia: Did you know that the flag of Turkmenistan is the same of Turkey’s , with the only difference being that it’s on a blue background?