Interest in Web-based and computer-assisted language testing is growing in the field of English for academic purposes (EAP). In this study, four groups of undergraduate EAP students (n = 120), each group consisted of 30 students, were randomly selected from four different disciplines, i.e. biology, political sciences, psychology, and law. The four groups were homogeneous regarding their English proficiency. Four course-specific web-based tests of academic vocabulary were administered to each group with regard to their specific disciplines. Questionnaires were employed to explore the EAP students' perceptions and self-efficacy concerning web-based language testing. Also, the perceptions of the four groups of undergraduates were compared in order to identify the differences among their attitudes. The findings would have implications for renewing assessment approaches and methods used in EAP instruction.