Although social capital plays an important role in organizational development, it has been overlooked to a large extent in Iran. Thus, it was deemed necessary to explain a model for promotion of social capital within the Ministry of Education that is based on cultural diversity. A categorical sample of 377 from among 1200 MoE personnel across all cultural groups was selected and given a specially constructed questionnaire with the internal consistency of 0.822. Data analysis lead to a structural model that included both internal and external factors. Results show that among factors external to the organization, Foundation and Strategy have a greater impact than the internal factors, although the overall impact of external and internal factors on social capital is equal. As for the consequences, the organizational factors, along with the personal factors, have the most impact.