The growing emphasis on STEM education in primary schools has raised concerns about whether pre-service teachers are adequately prepared to design and implement STEM lessons in real classroom contexts. Meanwhile, children from disadvantaged backgrounds often have limited access to STEM learning opportunities, creating a gap in both teacher preparation and educational equity. In response to these dual challenges, this study proposes a five-stage service-learning model, adapted from Kaye (2010), to enhance STEM teaching competency among pre-service primary teachers. The model integrates community needs assessment, lesson design, STEM teaching in authentic settings, reflective practice, and dissemination of results. Findings indicate that the model can be effectively incorporated into STEM-related coursework in teacher education programs, while also serving as a framework for community-based projects organized by student unions or volunteer groups. The proposed model not only provides meaningful experiential learning for pre-service teachers but also contributes to expanding STEM learning opportunities for disadvantaged children, thereby supporting both professional growth and educational equity.