The study aimed at evaluating Al-Aqeeda (Islamic principles) concepts in the Islamic studies Syllabus at the secondary level for the academic year 2000/2001 in the Sultanate of Oman. It aimed at answering the following questions: 1. what are the suitable Aqeeda concepts for secondary students? 2. how much are those Aqeeda concepts covered in the Islamic studies books at the secondary level? 3. what is the recommended suggestion for distributing Al-Aqeeda (Islamic principles) concepts throughout the secondary classes? In order to answer the first question the researcher prepared a list of Al-Aqeeda concepts by using different specialized references. He then established the validity of the list by presenting it to (25) specialists in Islamic studies. to determine about Islamic concept that are suitable to secondary schools syllabus. To answer the second question the researcher designed a an evaluation system to evaluate Al-Aqeeda concepts in the Islamic studies books in third secondary. Then he checked reliability by asking a collogue to analyze an arbitrary sample of (6) lessons out of (23)lessons in the books which constituted (26,8%). The correlation coefficient was (,98) which showed a high level agreement between then the two analysts. So, the evaluation system was considered reliable. To answer the third question, the researcher designed a questionnaire on distributing Al-Aqeeda concepts across the three secondary classes at the secondary level. He administered the questionnaire on a selected Islamic studies inspectors and teachers. The most important findings of the study were : 1. the total number of suitable concepts found by the study arrived at was (106) cover seven fields. Six of them reflect the basis of faith (Iman) while the seventh about the Al Eateqadat Al Faseeda. 2the current books has (70) Aqeeda (Islamic principles) concepts which constitutes (66.3 %) of the total concepts. 3 the concepts were distributed as follows: (57) for first secondary (16) for second secondary and (33) for third secondary. The study recommended that the Islamic studies syllabus at the secondary the level needs should be reviewed.