<![CDATA[Purpose of the study: This study aims to analyze the effect of STEM-based Problem-Based Learning (PBL) model on students’ learning outcomes in perimeter and area of plane figures in fifth-grade elementary school. The study focuses on comparing learning outcomes between students taught using STEM-based PBL model and those taught using conventional learning methods. Methodology: This study used a quantitative approach with a quasi-experimental method and nonequivalent control group design. The sample consisted of 49 fifth-grade students selected using purposive sampling. Data were collected using pre-test and post-test instruments. Data analysis was conducted using IBM SPSS Statistics 25, including normality, homogeneity, and Mann–Whitney U tests. Main Findings: The results showed that the average post-test score of the experimental class was higher than the control class. The Mann–Whitney U test indicated a significance value of 0.013 < 0.05, showing a significant difference. This indicates that the STEM-based PBL model has a significant effect on improving students’ learning outcomes in mathematics. Novelty/Originality of this study: This study highlights the application of STEM-based PBL specifically on perimeter and area of plane figures in elementary school context. It provides empirical evidence of its effectiveness in improving learning outcomes and offers a contextual and student-centered learning approach, contributing to the development of innovative mathematics learning models at the primary education level.]]>
