The conquest of Central Asia by Islamic Arabs, which was completed in the eighth century A.D., brought to the region a new religion and culture that continue to be dominant. The Arabs first invaded Mawarannahr in the middle of the seventh century through sporadic raids during their conquest of Persia. Available sources on the Arab conquest suggest that the Soghdians and other Iranian peoples of Central Asia were unable to defend their land against the Arabs because of internal divisions and the lack of strong indigenous leadership. The Arabs, on the other hand, were led by a brilliant general, Qutaybah ibn Muslim, and they also were highly motivated by the desire to spread their new faith (the official beginning of which was in A.D. 622). Because of these factors, the population of Mawarannahr was easily conquered. The new religion brought by the Arabs spread gradually in the region. The native cultures, which in some respects already were being displaced by Persian influences before the Arabs arrived, were displaced farther in the ensuing centuries. Nevertheless, the destiny of Central Asia as an Islamic region was firmly established by the Arab victory over the Chinese armies in 750 in a battle at the Talas River.

Under Arab rule, Central Asia retained much of its Iranian character, remaining an important center of culture and trade for centuries after the Arab conquest. However, until the tenth century the language of government, literature, and commerce was Arabic. Mawarannahr continued to be an important political player in regional affairs, as it had been under various Persian dynasties. In fact, the Abbasid Caliphate, which ruled the Arab world for five centuries beginning in 750, was established thanks in great part to assistance from Central Asian supporters in their struggle against the then-ruling Umayyad Caliphate.

During the height of the Abbasid Caliphate in the eighth and the ninth centuries, Central Asia and Mawarannahr experienced a truly golden age. Bukhoro became one of the leading centers of learning, culture, and art in the Muslim world, its magnificence rivaling contemporaneous cultural centers such as Baghdad, Cairo, and Cordoba. Some of the greatest historians, scientists, and geographers in the history of Islamic culture were natives of the region.

As the Abbasid Caliphate began to weaken and local Islamic Iranian states emerged as the rulers of Iran and Central Asia, the Persian language began to regain its preeminent role in the region as the language of literature and government. The rulers of the eastern section of Iran and of Mawarannahr were Persians. Under the Samanids and the Buyids, the rich culture of Mawarannahr continued to flourish.