Marwan ibn Muhammad ibn Marwan or Marwan II (688 - 750) was an Umayyad caliph who ruled from 744 until 750 when he was killed. He was the last Umayyad ruler to rule from Damascus.

Marwan took the caliphate after his cousin Ibrahim abdicated and went into hiding. Before becoming caliph, Marwan had served as governor of Azerbaijan. In this capacity he fought a costly war against the Khazar Khaganate, winning a Phyrric victory but being unable to secure his conquests.

Upon taking the caliphate, Marwan inherited an empire that was falling apart. Anti-Umayyad feeling had become very prevalent, espcially in Iran and Iraq, and the Abbasids had gained a lot of followers. As such, Marwan's reign as caliph was almost entirely devoted to trying to keep the Umayyad empire together.

Marwan would not be able to do so. Despite some early victories, he would be decisively defeated by Abu al-'Abbas al-Saffah on the banks of the Zab River . At this battle alone, over 300 members of the Umayyad family died. Following this defeat, Marwan frantically searched for refuge. Hoping to find it in the west, he traveled to Egypt but was caught while crossing the Nile and he was killed. His death signalled the end of the Umayyads in the East, and almost signalled the end of the Umayyads. The aftermath of his death brought about mass-killing of Umayyads by the Abbasids. Almost all Umayyads were killed, except for a talented prince Abd ar-Rahman who would sneak into Spain and reestablish the Umayyad dynasty there.