Abstract. This research aims to develop learning models P3E reasonable that can improve students' critical thinking skills. The model developed is named P3E, consisting of 4 (four) stages, namely organizing, investigation, presentation and evaluation. The study refers to the development stage of the development by Kemp. Comprehensive test design models using a pretest-posttest group design. Extensive test carried out in class X Islamic Senior High School 1 Mataram and Islamic Senior High School 2 Model Mataram. Analysis of the results of this development includes three aspects, namely: validity, practicality, and effectiveness of the developed model. The results showed: (1) validation experts 3,7 criteria valid, showing the model developed valid; (2) adherence to the syntax of the model developed from the observer obtained 98.09% votes in Islamic Senior High School 1 Mataram and 94.39 % Islamic Senior High School 2 Model Mataram. This shows the model developed impractical to implement; (3) Models developed effective to improve the critical thinking skills, although the n-gain critical thinking skills of students of 0.54 with the medium category. Based on the above results it can be concluded that learning model P3E developed, reasonable for use to improve critical thinking skills.