An Islamic flag is a flag either representing Islam, a concept or person related to Islam, or a state, military force or other entity associated with political Islam.
The flags of contemporary Islamic states tend to use one or several of the pan-Arab colors (black, red, white, green) and sometimes religious inscriptions such as the shahada or the takbir. The shahada has also become popular as an inscription on jihadist flags since the 1990s.
During the time of Muhammad, early Muslim armies and caravans flew simple solid-coloured flags (generally black or white) for identification purposes. In later generations, the Muslim leaders continued to use a simple black, white, or green flag with no markings, writings, or symbolism on it. Muhammad used flags of different colours in different Ghazwat (or campaigns commanded by Muhammad himself) and Saraya (or campaigns commanded by Sahabah, the companions of Muhammad). One of the flags used by Muhammad, the Black Standard, was known as al-ʿUqāb "the Eagle"; it was pure black, without symbols or markings. Its name and colour was derived from the flag of the Quraysh, one of the tribes of Arabia, whose flag was black with an eagle and was also known as "the Eagle".
Religious flags with inscriptions were in use in the medieval period, as shown in miniatures by 13th-century illustrator Yahya ibn Mahmud al-Wasiti. 14th-century illustrations of the History of the Tatars by Hayton of Corycus (1243) shows both Mongols and Seljuqs using a variety of war ensigns.