This study aims at recognizing the aspects of disagreement with regard to the applications and regulations of marriage (nikāḥ) according to the Ibadhi school. To achieve the aims and solve the problem of the study, the researcher has followed the inductive and analytical methodology through answering the following questions: • What are the Islamic legal regulations that the Ibadhi school has for the accepted disagreement? • What are the Islamic legal applications used by the Ibadhi school for this disagreement in the chapter of marriage? The study comprises a preface and two chapters. The first chapter discusses the legitimate rooting of the disagreement as seen by the Ibadhi school and its legitimate regulations with regard to nikāh, whereas the second chapter discusses the applications used by the Ibadhi school in this regard. The main findings of the study are as follows: • The accepted disagreement as seen by the Ibadhi school is every disagreement originated by a specialist Islamic scholar, provided that this disagreement does not interfere with a clear-cut text from Qur'an or Sunna, and is based on logical and legitimate reasons and justifications. The accepted disagreement of Islamic law (fiqh) is controlled by a number of regulations which are related to disagreement as a fact and to its approach of dealing with the disagreement. One of the legitimate regulations for the issue of the accepted disagreement is that the disagreement must be strongly originated, and that it is in the branches (furūc) of the Islamic Sharīda in which ratiocination (ijtihad) can be implemented, and not in the issues which have been resolved unanimously. With regard to the disagreeing parties and how they should deal with with each other, both parties should show respect, confidence to each other as well as rejecting all types of school related zealotry and following the right path wherever it is. The chapter on nikāḥ comprises a number of fiqh issues in which Islamic scholars are in disagreement with each other, according to the foresaid regulations, such as nikāḥ without permission of the parents, the pronouncement of triple divorce in one session, alimentation for the terminally divorced woman (nafaqat al-mabtūtah) and the waiting period (cidda) of the widow. In the light of the findings that this study has reached, the researcher concludes with a number of recommendations, some of these are as follows: • Study of other fiqh applications in which Ibadhis and other legal schools disagree in an accepted way. • Study of the rules on which opinions of the Ibadhis are based to consider the most likely ones. • Study of the legitimate goals that Islamic scholars agree upon with regard to fiqh issues in which Islamic scholars disagree.