The current flag of Iran (Persian: پرچم ایران parçam-e irân) was adopted on 29 July 1980, and is a reflection of the changes brought about by the Iranian Revolution.
Its field is a tricolour comprising equal horizontal bands of green, white, and red. The red emblem in the centre of the flag, designed by Hamid Nadimi, is a highly stylized composite of various Islamic elements: a geometrically symmetric form of the word Allah (“God”) and overlapping parts of the phrase La ilaha illa Allah(“There is no god but Allah”), forming a monogram in the form of a tulip. Written in white on the inner edges of the green and red bands is the repeated phraseAllahu Akbar (“God is great”) in a stylized version of the Kufic script used for the Qur’an. This writing renders the flag non-reversible.
Physical requirements for the Iranian flag, the exact shape of the emblem, and a compass-and-straightedge construction are described in the national Iranian standard. Wikipedia