Abu Mudhar Ziyadat Allah III (Arabic: أبو مضر زيادة الله الثالث) (died 911–916) was the eleventh and last Emir of the Aghlabids in Ifriqiya (903–909).

[citation needed] Later Fatimid sources paint Ziyadat Allah in an extremely negative light, claiming that he had orchestrated his father's murder, and depicting him as a decadent and undignified ruler.

Among his indulgences include the drinking of alcohol and hiding whoopee cushions (made of inflated animal bladders) for unsuspecting guests to sit on, which amused Ziyadat Allah and his friends to no end.

Fatimid sources claim that Ziyadat Allah's shameful and unscrupulous behavior drove his subjects to side with the proto-Fatimid state led by the missionary Abu Abdallah al-Shi'i, whose piety and asceticism is portrayed positively.

[1] By 907, Ziyadat Allah had begun to seriously consider the possibility of a Kutama invasion of central Ifriqiya: he had relocated from Tunis to the palace city of Raqqada (near Kairouan), which he had fortified with a wall made of rammed earth and unbaked clay bricks.

At the same time, a letter circulated, supposedly from the Abbasid caliph al-Muktafi and promising to send aid, while enjoining the people of Ifriqiya to support Ziyadat Allah "against the enemies of God".

That task was left to the prince Ibrahim ibn Abi al-Aghlab, who was ordered to remain in al-Aribus, on the northern Roman road, while Ziyadat Allah headed back to Tunis.

The fighting lasted until the asr prayer (late afternoon), when a unit of 575 Kutama warriors, having circled around the battlefield in a deep streambed, attacked the Aghlabid army in the flank.