Science learning in many school contexts continues to face two intertwined challenges: students’ declining interest in learning science and persistently uneven learning outcomes. Beyond pedagogy, the quality of learning materials matters because it shapes what students do, how long they persist, and what evidence of learning is produced. This article synthesizes research evidence (up to 2024) on the urgency of using science learning modules designed around Project-Based Learning (PjBL) to improve students’ interest and achievement. Using a targeted narrative review approach, we prioritized peer-reviewed meta-analyses, systematic reviews, and representative quasi-experimental and development studies that examined PjBL in science/IPA settings and reported outcomes related to interest, motivation, engagement, or academic achievement. Across the literature, PjBL shows a consistent positive association with achievement (e.g., medium-to-large effects in meta-analytic comparisons with traditional instruction) and small-to-moderate positive effects on motivation constructs, including interest and task value. Evidence from recent elementary and secondary school studies further indicates that well-structured PjBL can improve learning outcomes and student motivation when projects are anchored in clear driving questions, sustained inquiry, collaboration, formative assessment checkpoints, and explicit reflection. Based on this synthesis, we propose a practical module design framework that links PjBL module features to motivational mechanisms (autonomy, competence, relatedness, and task value) and to measurable learning outcomes. Implications are discussed for teachers, curriculum leaders, and module developers, emphasizing feasibility, assessment alignment, and equity of access.