Most of the construction projects are subject to change as some projects need to make some changes and modifications to the design, specifications, or any other work. These changes may be small and do not affect the duration and cost of the project, and they may be significant, resulting in increased working life and cost. Changes in construction projects have become a common and widespread phenomenon in Oman, with most government projects facing cost and time increases due to change orders. In this study, this problem was highlighted and the necessary solutions were found. The aim of this study was to assess the effect of change orders on construction projects and their causes. In order to achieve the aim of the study, the Governorate of Muscat was determined to conduct the study in it. This study was conducted on the basis of a literature review and several methods were used to collect information and data to obtain accurate results. interviews were conducted with all parties (clients, contractors, and consultants), and the questionnaire was also distributed electronically to 215 engineers in the private and government sectors and qualitative data (interviews) were analyzed by using the Constant Comparative method, as for quantitative data (questionnaire) by SPSS program. The research revealed many results, the most prominent of which is that change orders have a major role in increasing the duration and cost of the project. Finally, some recommendations were proposed that could con-tribute to the development of Omani projects and reduce the issuance of change orders.

Most of the construction projects are subject to change as some projects need to make some changes and modifications to the design, specifications, or any other work. These changes may be small and do not affect the duration and cost of the project, and they may be significant, resulting in increase...