abstract english language learning in iran has become significant in recent years, and english has been included in the curriculum of iranian schools and universities, and considerable attention has been paid to this language in our society. nevertheless, teaching and learning english in iranian schools has not been able to satisfy the specified goals, so different efl institutes have been established all over the country including the city of semnan. this study concerns about examining the opinions of the instructors and the students of english language institutes in iran (semnan) regarding the textbooks taught there. for that purpose, some primary information was obtained about the institute activity, facilities, rules, educational materials, teachers features, learners features and the way of assessment. also, the books taught were top notch, american english file, spectrum, english result, headway, true colors and interchange. then, two questionnaires were prepared based on tomlinson (2003) framework that had proposed validities of psychological validity, pedagogical validity and content and process validity. the questionnaires were handed to fourteen teachers and ninety-seven students. the teachers and learners evaluation of the books demonstrated that both teachers and learners supported the high psychological validity of the books. however, according to the teachers and learners, the books were problematical in the content and process validity. moreover, the teachers confirmed the pedagogical validity of the books.