Sultanate of Oman was one of the first MENA countries to enact Environmental Impact Assessment (EIA) legislations in 1982 by the Royal Decree (RD) 10/82 through "Law on the conservation of the environment and prevention of pollution". The main objective of this research is to evaluate the current EIA practice in Oman by assessing 1. The quality of the EIA reports from four major sectors with an established comprehensive review criteria.2.The perspective of two main EIA stakeholders namely the regulator and the developer through questionnaire survey. An additional objective was attempted to assess the efficiency of mitigation measures in a cement plant as a case study. The study found that the quality of 60 percent of EIA reports fall in the 'unsatisfactory' category. In-depth review of categories, subcategories, reveals that the key areas of EIA reports lack proper attention. The inadequacies are in areas related to identification and evaluation of impacts, mitigation of key impacts and consideration of alternatives. The survey results also found the EIA practice in the country has several weakness identified by both the regulator and developer. In general, factors influencing the quality of EIA system are highlighted. The case study in the cement plant clearly reveals the mitigation measures help in reducing the PM emission from 392 mg/m3 in 2009 to 43.8 mg/m3 in 2016.The study put forth a set of recommendations for the improvement of EIA process in the Sultanate of Oman.