Scientific literacy is a fundamental competency that enables students to explain scientific phenomena, evaluate evidence, and make informed decisions in addressing environmental, technological, and societal challenges. However, Indonesian students continue to demonstrate low scientific literacy achievement, as indicated by the Programme for International Student Assessment (PISA) 2022, highlighting the need for innovative instructional approaches from the elementary level. Although inquiry-based learning has been widely recognized as an effective approach for improving scientific literacy, previous studies have primarily examined its instructional effectiveness rather than systematically developing and validating inquiry-based instructional designs aligned with current scientific literacy competencies. Therefore, this study aimed to develop and evaluate an inquiry-based science learning design using the Educational Design Research (EDR) approach. The research consisted of four iterative phases: analysis and exploration, design and construction, evaluation and reflection, and design refinement. The participants included one expert validator, one elementary science teacher, and 32 elementary school students. Data were collected through expert validation, scientific literacy tests, and student response questionnaires and analyzed using descriptive and inferential statistical techniques. Results showed that the instructional design achieved a validity score of 93.33%, students' responses reached 86.40%, and scientific literacy scores increased from 58.84 to 84.31, with a significant difference (p < .001) and an overall N-gain of 0.69. These findings indicate that a systematically designed inquiry-based learning framework can effectively support scientific literacy development and provide a practical and theoretically grounded reference for improving elementary science education