<![CDATA[Elementary school student engagement in Natural and Social Sciences (IPAS) learning remains suboptimal because the psychological mechanisms shaping their intention to participate have not been comprehensively mapped. This study aims to evaluate a structural model based on Expectancy–Value Theory that explains the relationships among Attainment/Utility Value, Expectancy for Success, Affective Reactions, and behavioural intention in the context of IPAS learning. A quantitative approach with a cross-sectional survey design was employed. The study subjects consisted of 60 sixth-grade elementary students who had completed the entire IPAS curriculum. Data were collected using a closed-ended, five-point Likert scale questionnaire developed based on Expectancy–Value Theory constructs and validated by experts. Data were analysed using Partial Least Squares Structural Equation Modelling (PLS-SEM) to evaluate both the measurement and structural models. The results indicate that Attainment/Utility Value and Expectancy for Success positively influence Affective Reactions, while Affective Reactions strengthen students' Behavioural Intention to engage in IPAS learning. The study concludes that student learning engagement forms through the interplay of perceived learning value, beliefs about success, and positive affective experiences. These findings highlight the importance of designing meaningful IPAS instruction, providing structured learning support, and fostering positive emotional experiences to enhance student learning engagement sustainably.]]>
