Critical pedagogy has gained significance by the development of educational ideals, seeking equality at different levels of society (Freire, 1973). It has found its way into ELT in recent years. Since ELT practices are coupled with methodology courses in which different methods of teaching and learning are explained, teachers have become familiar with different methods and techniques of teaching, enabling them to take advantage of various trends in education. But it seems that ESP has not benefitted that much from insights gained into critical pedagogy because some of the ESP professors are those whose academic studies are not in ELT. Since, in Iran, the fields of study, other than ELT, do not take full advantage of English methodology courses, they seem not to be aware of innovations in English teaching. Thus, the development of a CP questionnaire for ESP context seems necessary. This paper reports the steps that were taken in developing and validating a critical pedagogy questionnaire for ESP context. In order to validate the questionnaire, 123 respondents were asked to answer the items. Three main sources of evidence were drawn upon to support the credibility of the questionnaires: reliability, content and construct validity. Opinions from a group of experts and a pilot study guaranteed the content validity of the questionnaire, respectively. Furthermore, Principal Component Analysis was used to measure the construct validity of the questionnaire, which resulted in the items loading under five major subcomponents. The reliability coefficient was also calculated for all five subcomponents, using Cronbach's alpha. The results of the study showed that this questionnaire could be a valid and reliable instrument for examining the criticality of ESP teachers. The questionnaire may be used in studies aiming to examine whether Iranian ESP teachers' practices, in particular, are consistent with the principles of critical pedagogy. Furthermore, the extracted components can be useful guidelines to increase the understanding of ESP practitioners of the principles of critical pedagogy.