The study aimed to make a proposed framework to expand the School accreditation in post-basic Education Schools in the Sultanate of Oman, determine the degree of approval of expert opinions about the study's questionnaire. (Requirements for expanding School accreditation culture, methods of expanding School accreditation culture, and the challenges they may face expanding School accreditation culture). The study also aimed to determine the degree of approval of expert opinions about the importance of (Requirements, and methods) to expand the School accreditation in post-basic Education Schools in the Sultanate of Oman. The study used the descriptive method and experts opinions (Delphi) of 36 experts who have PHD and master degrees in the educational management in Oman and also from external experts specialized in fields related to quality and accreditation in order to prepare the proposed framework. The result of the study in the first round showed that the approval rate in the first section, (Requirements) was (81.8%), While in the second section (methods) the approval rate (86.1%). The third section (challenges) received the approval rate (66.8%). The experts agreed to delete the section (challenges) of the second round, which focused on determining the degree of importance of only two sections (requirements, and methods). The section of (requirements) on the approval rate (79%), while the section of (methods) won the approval rate (82.4%) Based on the results of the two rounds, the proposed framework includes a group of objectives, philosophical basis and ways of application. The framework shall be executed through two main stages, the first included preparation and configuring employees in the post- basic education schools to accepts the school accreditation culture through the following: 1- Analyzing the current culture in post-basic Education schools and measuring it. 2- Making positive impressions for employees in post-basic Education schools to make a change in the current culture. 3- Preparing for the expected resistance against the school accreditation culture expanding. 4- expanding the school accreditation culture and continuous counselling. The second stage, The Ministry of Education shall fix the policies and strategies for applying the school accreditation culture and review the structural organization of schools or amend it, to help in expanding it.