Purpose: The purpose of this study was to design and validation of a desirable model for developing critical thinking in the first-grade high school curriculum based on the upper documents of education in Iran. Methodology: This research is an evaluation study which the field research has been used in doing that. In this study, three methods were used to collect data. With reviewing the literature review of the research, the components of common critical though by various theorists and researchers were specified then, the national curriculum was analyzed with respect to the components of critical though. In the next step, the proposed model was designed and validated according to the components emphasized in the upper documents. A researcher-made questionnaire was used for validation. The research community consists of all curriculum practitioners who are as permanent members in Iranian Student Planning Association (500 people). In this research, simple random sampling method was used for sample selection and Morgan table was used to determine the sample size (217 ones). Findings: In addition to descriptive statistics, Chi-square method with an acceptable error rate of 0.05 was used for data analysis. The results of the research indicate that all the hypotheses and the appropriateness of the proposed model have been confirmed by specialists. Discussion: According to the results of the research Reviewing the objectives, content, learning activities and evaluation practices in Iranian first-grade high school education system with emphasis on developing the critical thinking in students can be proposed.
