This study is aimed at setting proposed mechanisms for managing investment of Waqif in public schools in the Sultanate of Oman in light of the system input. The study has used the descriptive approach via applying the questionnaire regarding collection of data and information. The study community consisted of all the Sultanate's public school headmasters and their assistants in the school year 2019/2020 totaling 1578 , and the study was applied to a sample of 265 headmasters and assistants. The study concluded that the estimates on part of the questionnaire sample members concerning the proposed mechanisms for managing investment of Waqif in public schools in the Sultanate of Oman in light of the system input were "High" in the whole of the mechanism and its five fields as shown by the responses of the sample members. The first position was held by the domain concerned with the financial control of the Waqif investment followed by the domain concerned with planning the Waqif investment holding the second position, The third position went to the domain concerned with the dissemination of the Waqif culture while the domain concerned with regulating the Waqif investment held the fourth rank, and the fifth and last rank went to the domain concerned with the employment of the Waqif funds. The study also showed no differences of statistical significance at the indicator's level (α≤ 0,05) among the averages of responses by the study sample members regarding the proposed mechanisms for managing the investment of Waqif in public schools in the Sultanate of Oman in the five domains and the whole of the tool attributed to the social gender variable and the job designation one. The study made a number of recommendations on developing the management of Waqif investment in public schools in the Sultanate of Oman, notably setting a clear strategy by the Ministry of Education to be followed by school administrations when managing Waqif investments in the Sultanate's public schools, and every school has its own Waqif supervised by the Ministry of Endowments and Religious Affairs.