The aim of this study is to analyse the origins and the development of the Ibadi madhhab and its relationship to the Sunni schools in the early centuries of Islam. There are some important questions facing this issue, for example whether or not the Ibadi fiqh developed independently of the Sunni fiqh, which was the role of the early Ibadi authories, whether or not the position attributed to Jabir b. Zayd in the formation of Ibadi fiqh could be accepted. I would argue that the solution depends on a critical analysis of Ibadi literature. It is possible, I would submit, to place them in the context of Islamic social and legal history. My research is based on the Ibadi tabaqat and fiqh works and mainly on some Ibadi manuscripts, whose content seems to be ancient. Not only will the anlysis of these texts make the process of establishment of the Ibadi madhhab clearer, it will also provide a much stronger basis for the study of the earlier centuries of Islam.