Incorporating climate change into education is critical for building a sustainable future and empowering the next generation to take action. This study aims to explore how a project-based club program influences middle school students' action competency in responding to climate change. For this aim, ten students who participated in a project-based club program in a boys' middle school were selected. A pre-test on relevant knowledge was surveyed, students' behaviors during the program were observed, and in-depth interviews were conducted after the program. The results revealed that students showed a better understanding of climate change and carbon neutrality concepts, increased sensitivities to climate change, deepened reflections on climate change activities, improved communication and decision-making abilities, and improved willingness to take action in climate change mitigation activities. It was concluded that the project-based club program has positively influenced students' action competency in responding to climate change. [For the full proceedings, see ED629086.]