With the development of information technology, organizations have applied e-learning system to train their employees in order to enhance their performance. In this respect, applying the web-based training system will enable organizations to train their employees quickly and effectively anywhere at any time. Using some factors such as flexibility of web-based training systems, system interactivity, system enjoyment and some moderators including age, gender and experience, this paper aims to extend the Unified Theory of Acceptance and Use of Technology (UTAUT), as a way to explain the employees’ intention to use web-based training system. A total of 290 employees participated in this study. The findings of the study revealed that performance expectancy, facilitating conditions, social influence and system flexibility have direct effect on the employees’ intention to use the web-based training system, while effort expectancy, system enjoyment and system interactivity have indirect effect on employees’ intention to use the system.