The current study aims at finding out (The Effectiveness of Suggested Instructional Program Based on the Theory of Creative Problem Solving on the Achievement of Students of Fourth Literary Stage in Geography and Developing their Serious Thinking). (65) students from the fourth literary class, with (33) students for the experimental group, and (32) students for the control group. The preparation of the program went through four phases (analysis, design, implementation, and evaluation), where the program was planned with all its components (objectives, content, methods and methods, activities, and evaluation tools) in line with the problem-solving theory. It is a multiplex test type with four alternatives to measure the levels (knowledge, understanding, application) and (6) essay items to measure the levels (analysis, synthesis). The second tool was to prepare a test that measures serious thinking, consisting of (30) test items. And through the validity and reliability of the two tests and the calculation of their psychometric characteristics. The results showed the superiority of the students of the experimental group over the students of the control group who studied the same subject in the traditional program in the achievement test and in serious thinking.