Globalization has proposed a new form of citizenship called Global Citizenship. Despite increasing the attention to this concept in the different educational systems, there is little agreement on its definition, dimensions, and components. This study aims to develop and test a model for global citizenship education in the Iranian Education System, using the Sequential Exploratory Mixed Methods Design (qualitative and quantitative method). The participants in the qualitative part include 10 experts and policymakers in education selected by the Judgmental Sampling Method and Theoretical Saturation Technique. The statistical population in the quantitative part includes all the sociology teachers of Tehran, of which 240 people selected as the research sample by the Cluster Sampling Method. To collect data, the semi-constructed interview tools, and a researcher-made questionnaire, used. Data analysis methods in the qualitative part are the Thematic Network Analysis Method (basic, organizing, and global themes), and in the quantitative part include T-test, Wilcoxon Test, and Confirmatory Factor Analysis (CFA) using SPSS and PLS software. Qualitative Findings show a model includes 3 global themes (knowledge, attitude, and skill); 21 organizing themes, and 147 basic themes. The test results of this model in the quantitative section show a very strong Fit of the global citizenship education model in the Iranian Education System. It also showed that all dimensions and components of the model have great importance to the teachers.