The Flag of Yemen (Arabic: علم اليمن) was adopted on May 22, 1990, the day that North Yemen and South Yemen were unified. The flag is essentially the Arab Liberation Flag of 1952, introduced after the Egyptian Revolution of 1952 in which Arab nationalism was a dominant theme. The Arab Liberation Flag served as the inspiration for the flags of both North and South Yemen prior to unification, as well as for the current flags of Egypt, Iraq, Sudan, and Syria.
According to the official description, the red stands for the unity and the bloodshed of martyrs; the white for a bright future; black for the dark past. The flag's design is also similar to the design of the flag of the German Empire, albeit inverted.
The North used the flag on the right (the flag of the Mutawakkilite Kingdom of Yemen) from 1927 to 1962, when it became the Yemen Arab Republic. The flag of the Yemen Arab Republic was the Arab Liberation Flag with a green star in the center of the white band.