One of the advanced technologies in e-learning deals with the systems’ ability to fit the students’ preferences. It emerged based upon the common conception that every person has different learning style. However, despite the many options of learning style models toward using personalized e-learning, there are considerable challenges to assess the usability degree of the e-learning. The aim of this study is the evaluation of usability of personalized adaptive e-learning system that has been developed based on students’ learning style and initial knowledge level. The study involved 62 Computer Network students in one of the public vocational secondary schools in Yogyakarta, Indonesia. To measure the usability, the USE Questionnaire, which consists of four indicators (usefulness, ease of use, ease of learning, and satisfaction) represented by 30 questions with four possible Likert scale options, was distributed to the students. The research finding indicates at first the usability of the adaptive e-learning system for the students was well accepted in all aspects of usability. Next, the multiple linear regression result showed that the variables usefulness, ease of use, and ease of learning simultaneously influence satisfaction. Lastly, the regression results also revealed that the variables usefulness and ease of use partially influence satisfaction, while the variable ease of learning does not.