One prominent characteristic of today’s society is the huge volume of information that is being shared by a growing number of users and applications. As the result, this information must undergo a process to obtain uniformity of the terms. Subsequently, information integration has gained importance in the provision of focused and structured information for more comprehensive purposes in the educational domain in recent time. Although the Ministry of Higher Education in Iraq has a Web portal that provides information pertaining to Postgraduate studies and research, the retrieval for information supported by the Website still pose a major obstacle to students. To address this problem the researcher of this study propose an ontology-based framework for the implementation of the process of information integration in four well-known universities in Iraq. This research engages the application of Uschold and King Ontology building methodology to develop the domain ontology to support information interoperability among the selected Iraqi universities. Then, a query system is developed for assisting postgraduate students in their search for information related to postgraduate studies.