The objective of the study was to evaluate and assess the readability of English reading materials in the twelfth-grade textbook published by Darussalam Press. Numerous studies have been conducted to investigate the adequacy of reading materials in English textbooks, revealing that some materials are insufficient for the students' levels. Furthermore, there has been no scholarly investigation conducted on this particular literary work. The study employed a quantitative descriptive research design, with the English Lesson 6 textbook for twelfth grade, published by Darussalam Press, serving as the research object. The textbook comprises ten reading materials that are centered on the comprehension of written texts. The study was centered on the analysis of the reading materials contained in the book, with a particular emphasis on the evaluation of the English textbook's readability. The book contains five distinct genres. Examples of text types include analytical exposition, descriptive text, spoof text, anecdote text, and recount text. The methodology employed for data collection involved the utilization of observation and document analysis. The Flesch Reading Ease (FRE) formula was utilized to determine the readability level. The process of content analysis involves the assessment and evaluation of the written materials contained within English textbooks. The findings of the study indicate that the English textbook contained a total of ten reading texts. These texts were categorized as follows: one analytical exposition text, five descriptive texts, one spoof text, two anecdote texts, and one recount text. The study utilized the Flesch Reading Ease (FRE) formula to conduct an analysis, revealing that only six texts were eligible for examination. The present study conducted an analysis of the readability level of six texts, revealing that two of the texts were classified as Standard level, two were categorized as fairly difficult, and the remaining two were classified as Difficult level. Out of the six texts analyzed, only two were deemed appropriate for senior high school students based on their readability level. The titles of the texts were "Albania" and "A Brief about TV." Furthermore, the researcher conducted an assessment of the readability of the text by analyzing the factors that impact readability and utilizing readability measurements. The findings of the analysis indicate that several factors have an impact on readability, including but not limited to vocabulary awareness, background knowledge, organization, discourse phenomena, and length of passage. The present study involved an examination of vocabulary awareness in two reading materials, namely "Mother and Moral Education" and "The Whistle". A total of ten instances of vocabulary awareness were identified. The text titled "Albania" exhibited a total of twelve instances of vocabulary awareness, while the text titled "Arabic Calligraphy" demonstrated seven instances of vocabulary awareness. Similarly, the text titled "A Brief about TV" displayed a total of sixteen instances of vocabulary awareness, while the text titled "Asia" showcased fifteen instances of vocabulary awareness. The examination of prior knowledge derived from the texts revealed that both the teacher and students possessed equivalent background knowledge. In the examination of passage length, it was observed that two texts, namely "Asia" and "The Whistle," contained a total of five hundred words. The present corpus comprises two texts, each consisting of approximately three hundred words. The first text is entitled "Albania", while the second text provides a brief overview of television. This brief composition aims to identify two texts titled "Mother and Moral Education" and "Arabic Calligraphy" in a concise manner. The first text explores the role of mothers in providing moral education to their children, while the second text delves into the art of Arabic calligraphy. Both texts are of interest and relevance to their respective fields of study. The research is subject to certain constraints, primarily centered on the evaluation of the readability level of reading materials contained within a single textbook. An additional constraint pertains to the fact that solely the Flesch Reading Ease formula is employed for the computation of data analysis. In summary, it is recommended that teachers utilize readability formulas to furnish pupils with suitable reading materials, while also encouraging further research into the broader context of readability