The current research investigates the lexical coverage of reading passages required for achieving the minimal and optimal levels of reading comprehension in a foreign language. More specifically, the aim of the study is to identify the word frequency bands within the reading passages in the English tests of The Higher Education Institutions Examination that surpass the 95% and 98% lexical coverage thresholds needed for minimal and optimal reading comprehension. Fifty reading passages in the exams held in the last decade (2012-2021) were analyzed in the Compleat Web VP system to determine their lexical coverage. The results indicate that when the reading passages are analyzed separately, the vocabulary needed for minimal reading comprehension varies between 2,000 and 18,000 word families. Similarly, the vocabulary required to achieve an optimal level of reading comprehension ranges from 3,000 to 18,000 word families. In addition, upon analyzing reading passages grouped by year, it becomes evident that the word families necessary for achieving minimal and optimal levels of reading comprehension are found in the 4K and 8K word frequency bands, respectively. These findings suggest that when developing a curriculum for the entire high school period, emphasis should be placed on teaching the most frequent 8,000 word families to avoid inconsistency between taught and tested vocabulary. Furthermore, given the substantial number of word families to be addressed, it is important to establish opportunities for both intentional and incidental vocabulary teaching methods. Moreover, it is essential to acquaint learners with vocabulary learning strategies that enable them to acquire vocabulary indirectly.