The founder of this sect is Abdullah ibn Ibad (d. 86 AH). Some believe that Abdullah was the political leader of this group and that the scientific and religious leadership was under the responsibility of Jabir ibn Zayd al-Omani. Abdullah initially accompanied Nafi ibn Azraq (the founder of the Azraq sect), but after learning of his extremist views, he separated from him. Abdullah left during the time of Marwan ibn Muhammad and Marwan's army fought him in a place called Tabala. Jabir ibn Zayd is one of the leaders of the Ibadi sect and is from the same tribe. Therefore, Jabir's preaching was effective in Oman and many people of that land accepted the Ibadi sect. Apparently, at the same time as the dissolution of the Umayyad government in 132 AH, Julandi ibn Mas'ud succeeded in establishing the Ibadi government in Oman. However, soon after, the Abbasid Caliph Saffah sent an army to Oman and destroyed the Julandi government in 134 AH. After a while, the Ibadis regained control of Oman, and this situation continued for about a hundred years until disagreements arose among the Ibadis, after which an army led by the Abbasid Caliphate invaded Oman and once again overthrew the Ibadis, but the majority of the people remained Ibadis.

The Ibadis are the most moderate sect of the Khawarij and the only remaining sect of them that is present today in Oman and parts of North Africa. The current royal family of Oman is also Ibadis and is from the same tribe.

Al-Shahristani describes the most important Ibadis beliefs regarding the issue of faith and disbelief as follows:

1 - The perpetrators of major sins are not believers; rather, they are disbelievers.

2 - The disbelief of the perpetrators of major sins is a form of disbelief in blessings, not disbelief in the nation or religion.

3 - The perpetrators of major sins are monotheists, not polytheists, because they accept the One God.

4 - Marriage and inheritance with major perpetrators is permissible, and killing them is not permissible, unless there is a war involved.