Whether acknowledged or neglected by educators, the hidden curriculum is present in every institute. Therefore, studying the hidden curriculum is essential to understand how it functions within an English language institute’s setting and among those within it. The purpose of this study was to design and validate a scale to measure language teachers’ perspectives on English as a Foreign Language (EFL) hidden curriculum by the application of the Rasch model. The review of the literature indicated the lack of sufficient research on the investigation of EFL hidden curriculum components in the view of EFL teachers. To fill the existing gap in the literature, a 40-item questionnaire was devised and validated, then 164 Iranian EFL teachers, teaching at different language institutes were asked to reply to the questionnaire. In this study, hidden curriculum components were based on Saylor, Alexander, and Lewis’ (1981) perspectives. Accordingly, items were classified into three different constructs, namely the social atmosphere (including 15 items), the organizational structure of the English Language Institute (consisting of 14 items), and the interaction between teachers and learners (including 11 items). The results showed that the questionnaire items fitted the Rasch model after removing six items from the scale. Moreover, it was confirmed that the scale enjoyed suitable reliability. This proposes that the questionnaire is potentially valid and can be used as a measure of EFL hidden curriculum. One of the study implications is that the questionnaire designed and validated in this study can be used as a research tool in future research to assist policymakers and material designers, institutions’ administrators, and language teachers to be considered for future decision making, and designing materials. It also can be used as a research tool to measure the relationship between EFL hidden curriculum and other variables in future research.
