The Sultanate of Oman is an and country with rapidly developing economy and a high population growth rate. Together, they have increased the demand for freshwater. In response, the Sultanate has developed well fields and installed desalination plants across Oman. Albeit meeting the demand for freshwater, such investments are straining the country's financial and natural resources. Experience in several and and semi-arid countries indicates that greywater can be a cost-effective alternative source of water. However until recently, lack of data on this aspect has been a barrier to arriving at such a conclusion. Ahmed et al. [1], Jamrah et al. [2] and Prathapar et al. [3] have recently collected relevant data, which reveals that there are several factors constraining treated greywater reuse in Oman. They are categorized as quantity, quality, financial, legal, social and institutional constraints in this paper. Possible means of overcoming these constraints are also discussed.