Accounting is an art of recording financial transactions. Recording transactions can be performed by a different method or approach. Students are required to be able to think critically logically, analytically, and systematically to solve a wide variety of problems that exist in each material. Instructional materials should be made based on the specific methods in order to attract students to be active in the following study. Inquiry learning method is a method of learning that encourages students to think critically, analyze a problem to find alternative solutions to problems. The purpose of this research is to develop inquiry-based teaching materials accounting to improve critical thinking skills and learning achievement in students. Teaching materials developed in the material bank reconciliations and other transactions and adjustments. This research method used is research and development (R & D) which adapts the model of development research Borg & Gall. Subjects in this study is a class XI student of Accounting at SMK Negeri 1 Surakarta. The results of the validation and testing of the product showed that decent teaching materials used in learning. Teaching materials can enhance critical thinking skills and learning achievement.