This study aims to develop an integrated Project-Based Learning (PBL) model based on Values, Attitudes, Skills, and Knowledge (VASK), specifically designed for small-sized schools and mixed-grade classrooms. Employing a phenomenological study approach with a mixed-methods data structure, the research explores two key questions: What are effective multi-grade teaching models? and how does a teacher professional development program (PD) enhance teachers' ability to implement multi-grade instruction? The study was conducted in collaboration with 45 teachers from five schools across various subjects, including science, mathematics, technology, language, and social studies. It investigates the design and implementation of VASK-based PBL within both classroom and community settings. Data were collected through classroom observations, focus group interviews, and student-teacher reflective journals to assess the model's effectiveness and adaptability. Findings revealed that the VASKPBL PD program fosters interdisciplinary learning, community engagement, and student empowerment, enhancing critical thinking, problem-solving, and social responsibility. The study also demonstrated that teachers from all five schools successfully designed multi-grade classroom learning management by integrating inquiry-based learning with context-based education rooted in the local environment. This model offers a practical framework for schools facing resource and staffing limitations, providing meaningful learning experiences that support both academic achievement and social development. Additionally, the study contributes to the PBL literature for mixed-grade settings, highlighting the importance of community-based, values-driven education in promoting equitable learning opportunities for small schools.