A specific design practice namely design thinking involves a problem-solving approach to deal with complex problems. Students had meaningful experiences in empathy, creativity, critical thinking, teamwork, and risk-taking, which prepared them for the next step of their learning or a career in the 21st century. A real-world problem is one of strategies for employing the obtained knowledge and particular skills to solve the problem. The study aims at cultivating five design thinking competencies of high school students by using real-world problem. The program was then designed to have fun, age-appropriate, practical, hand-on activities, and teamwork. After participation in the program designed, the high school students improved their design thinking competency and achieved the expected level of proficiency. Real-world problem motivated students' autonomy to find the right topic, create ideas, select the promising solution, construct a prototype, and test with the user. The students played an active role in gaining direct experiences. Moreover, a more favorable climate for learning by facilitators, teamwork, and program activity encouraged active participation of the students.