Curricular knowledge, as one of the key components of teacher knowledge base, has received scant attention in second language teacher education. To address this gap, this study was conducted to explore the curricular knowledge base of Iranian English language teachers. Data were collected using a questionnaire developed based on the components of curricular knowledge mentioned in Roberts' (1998) model. Results showed that the teachers possessed an appropriate knowledge of a few components of curricular knowledge, including their awareness of materials suitability and structures of the lessons, their ability to judge the content of the materials or to translate the instructions in teachers' manuals into practical activities, and their ability to teach English as a Foreign Language textbooks. However, they showed a less developed knowledge base on half of the components of the curricular knowledge which comprised, inter alia, their cognizance of the content of the exams, cultural aspects of the textbooks, and learner-cantered activities. These findings imply that measures should be taken to help teachers fill the existing gaps in their curricular knowledge through teacher education courses.