Introduction: In the last decades, several attempts have been made to internationalize of higher education. This study aimed to analyze factors influencing the internationalization of medical education from viewpoint of faculty members. Methods: This is a descriptive and cross-sectional study. The statistical population included faculty members of medical school at Shahid Beheshti University in which 205 members by using Cochran formula were selected as the sample. The research instrument was a researcher-made questionnaire based on documentary studies so that its validity determined by content validity method and using the opinions of five academic experts and the reliability calculated by Cronbach's alpha coefficient 0. 897. Data were analyzed using descriptive statistics (Mean & Standard Deviation) and inferential statistics (One-Sample T-Test & Friedman Test) through SPSS. Results: The mean of economic domains (3. 82± 0. 641), cultural (3. 37± 0. 735), political (3. 73± 0. 452), academic (3. 64± 0. 620), managerial (3. 65± 0. 749) and information (3. 88± 0. 732) were moderate, and Friedman's test results showed that political and cultural domains had the highest and the lowest impact on internationalization of medical education respectively. Conclusion: It can be concluded that all the identified factors affecting the internationalization of medical education, but factors such as increasing the financial resources for internationalization, increasing optimism about the presence of international students, facilitating the issuance of passport and visas, paying attention to internationalization in the university vision, improving organizational structure for international cooperation and communicating with international associations is more important.