This paper reports a study which investigated if there was a match between students’ English vocabulary size and the vocabulary load of a locally produced textbook. The analysis of the passages of the pre-university English textbook currently in use in Iran’s education system using RANGE program indicated that in order to comprehend the texts, students need to know not only words from 2000 high frequency word list, but also words from academic and low frequency lists. On the other hand, results of the 2000 vocabulary level test administered to 464 Iranian pre-university students, male and female, showed that students did not possess sufficient vocabulary knowledge in order to comprehend the texts and that their vocabulary knowledge was limited far below 2000 words. Other analyses of the textbook, including exercises and word glosses provided more evidence for the inadequacy of the textbook. The paper concludes that the pre-university textbook is flawed in terms of the required principles and standards in materials development which results in students’ frustration and disappointment in learning English. The findings of the study are discussed, which should be of much interest to local and international ELT stakeholders, especially textbook writers.
