This paper examines the influence of the external factors of the Technology Acceptance Model (TAM) on the perception of SAP system usability. TAM is a theoretical framework often used to analyze technology acceptance, while the SAP system is a complex Enterprise Resource Planning (ERP) system widely used in organizations. The external factors considered in this research are system complexity, system performance, user manual, social impact and work compatibility. A questionnaire was used to analyze the data using the structural equation modeling (SEM) technique. The results show that of the five external factors mentioned, only two factors have a statistically significant influence on perceived ease of use, namely system complexity and system performance. By considering external variables, these results can provide a deeper understanding of users' attitudes towards SAP ERP. This can help to better analyze and interpret the research results and suggest more effective strategies for the implementation and adoption of the system in companies.