The present study is aimed at designing a tool to evaluate the bilingual program in private schools in the Sultanate of Oman according to multiple decisions model of Stufflbeam (CIPP). The study sample consisted of ( 436) individuals of whom ( 64 )are administrative, (14) teachers and (58) school supervisors. The respondents were selected stratified randomly to ensure proper distribution of different categories of the study population ( gender and nationality). Scientific steps were followed in the construction of this tool. The study tool consisted of ( 92 ) statements that are divided to (4) main dimensions and (8) sub-dimensions. The researcher followed the descriptive approach to complete the study and used the Stufflbeam model in designing the tool which focused on the main dimensions which are context evaluation, input evaluation, process evaluation, and product evaluation. The researcher used appropriate statistical methods to answer the study questions. Results of the study showed that the current evaluation tool of the bilingual program contains psychometric characteristics required in terms of validity that is calculated in two ways: face Validity and Construct Validity. In addition, the results of the study also showed the tool has a high level of reliability, which is calculated in two ways: test-Rerest, and Coefficient Alpha. The findings were discussed in the light of the theoretical framework, and the results of previous studies on the subject. This resulted in a set of recommendations and proposals, including: the importance of implementing the tool proposed in this study by the concerned authorities to assess the performance of private schools in the Sultanate. In addition, it confirmed the need for conducting evaluation studies based on the use of a particular model of global evaluation models as it gives the researcher a procedural model and scientific steps, which grant reliability in evaluation. The study also recommended the need to evaluate the bilingual program as a curriculum with its goals and future vision.