The purpose of this study was to evaluate the secondary school Islamic Education textbooks according to the opinions of the teachers and the students. More specifically, the study attempted to answer the following questions : 1. How do the teachers rate the appropriateness of the secondary school Islamic Education textbooks? 2- How do the students rate the appropriateness of the secondary school Islamic Education textbooks ? 3- Are there any statistically significant differences between males and females in their ratings of the appropriateness of secondary school Islamic Education textbooks? 4- Are there any statistically significant differences between grade levels in the students' ratings of the appropriateness of Islamic Education textbooks? 5- Based on the teachers' gender are there any statistically significant differences in their ratings of the appropriateness of the Islamic Education textbooks ? The population of the study consisted of all the secondary school students and their Islamic Education teachers in the Directorate of Muscat in the 1994 - 1995 academic year. The sample of the study was made up of (70) teachers and (542) students. The researcher constructed two questionnaires : one for the teachers and the other for the students . Both questionnaires on the school textbook and were divided into the following seven categories objectives, content and its organization, instructional media, evaluation, activities, language, and production. The two questionnaires used a five -point Likert scale. The validity of the questionnaires was established via a panel of (15) judges. The reliability of the questionnaires was established by calculating the internal consistency coefficient (Cronbach's Alpha = 0.88 for the students' questionnaire and 0.95 for the teachers' questionnaire ), and by the test-retest method for the questionnaire of the students which yielded a reliability coefficient of 0.69. The statistical techniques used in this study were : the t-test and the analysis of variance (ANOVA). The t-test was used to determine the effect of the gender of the students and the teachers on their ratings of the appropriateness of the Islamic Education textbooks . The ANOVA was used to determine the effect of the grade level on the students' ratings of how appropriate the textbooks were . The study arrived at the following results concerning the appro priateness of the Islamic Education textbooks : 1- The means of the teachers' and students' ratings of the first secondary Islamic Education textbook were (64.38) and (66.97) respectively. 2- The means of the teachers' and students' ratings of the second secondary Islamic Education textbook were (66.30) and (66.13) respectively. 3- The means of the teachers' and students' ratings of the third secondary Islamic Education textbook were (70.24) and (66.17) respectively, 4- Based on the teachers' and students' ratings, the most appropriate categories were : the language of the textbooks, their production, and the objectives. The categories of instructional media and activities were the least appropriate. 5- There were statistically significant differences in the students' ratings of the appropriateness of first and second secondary Islamic Education textbooks based on gender The female students rated the appropriateness of the textbooks more highly than the male students. 6- There were no statistically significant differences in how appropriate the textbooks were, based on the teachers' gender or the students' grade level .