This study was carried out to analyze to what extent students have been evenly exposed to the Critical Thinking Skills through the exercises provided for in the KBSM Islamic Education textbooks. The sample in this study consisted of upper secondary (form 4 and form 5) Islamic Education textbooks. 278 exercises and 317 activities in the textbooks were analyzed. An instrument entitled “Critical Thinking Skills Code Analysis” was developed by the researchers, based on the works and ideas of past researchers and experts in the field, forming the basis for the instrument. Data was collected through the use of different types of forms. Frequency count and the percentages were used for data analysis. The results show that most of the exercises and activities in the textbooks focussed more on the Information Gathering and Applying Skills, followed by the Inference Skills and Decision Making skills. There were no exercises directed towards Analogy Forming Skills.