This study aims to examine the effect of STEAM (Science, Technology, Engineering, Arts, and Mathematics) learning on the critical and creative thinking skills of fourth-grade elementary school students. Specifically, it compares the improvement of these skills between students who participate in STEAM-based learning and those who receive conventional instruction. The research employs an experimental method with a pretest-posttest technique, using test questions as the instrument to assess critical and creative thinking abilities. The study follows a Nonequivalent Control Group Design, involving two classes: Class IV A as the experimental group and Class IV B as the control group. The results indicate a significant difference in critical thinking skills, with a 2-tailed significance value of 0.001 < 0.05, and in creative thinking skills, with a 2-tailed significance value of 0.012 < 0.05. These findings suggest that there is a difference in the average scores of critical and creative thinking skills between the two groups. Therefore, it can be concluded that HaH_a is accepted and HoH_o is rejected, meaning that the implementation of STEAM-based learning in the experimental class positively influences the improvement of elementary students' critical and creative thinking skills.