Students’ learning anxiety in Integrated Science and Social Studies (IPAS) remains a significant issue that negatively affects their engagement, concentration, and learning outcomes in elementary schools. This condition highlights the need for instructional approaches that can create active, contextual, and meaningful learning experiences. This study aimed to analyze the effect of the STEM (Science, Technology, Engineering, and Mathematics) approach on the learning anxiety of fifth-grade elementary school students in IPAS learning. The study employed a quasi-experimental method using a pretest–posttest control group design. The participants consisted of fifth-grade students divided into an experimental group and a control group. Data were collected using the Generalized Anxiety Disorder-7 (GAD-7) questionnaire. The data were analyzed using quantitative and qualitative techniques. The results of the independent-samples t-test revealed a significance value of p < 0.001, indicating a statistically significant difference in learning anxiety between students in the experimental group, who received instruction through the STEM approach, and those in the control group, who experienced conventional instruction. The posttest data distribution further showed that the most frequently occurring score (mode) in the experimental group was 4, which falls within the category of minimal anxiety. In addition, students in the experimental group demonstrated a reduction in learning anxiety with a moderate level of improvement based on the N-Gain analysis. It can be concluded that the implementation of the STEM approach has a significant effect on reducing students’ learning anxiety in IPAS learning at the elementary school level. The findings imply that the STEM approach can foster more active, contextual, and meaningful learning experiences, thereby increasing students’ engagement in the learning process.