This chapter explores whether teaching critical thinking can help reduce vaccine hesitancy and skepticism. Based on research in social and cognitive psychology, we argue that anti-vaccine views are often not due to a lack of knowledge but are shaped by motivated reasoning and cognitive biases. We present the “Just Think!” program—an educational intervention used in Polish high schools—to improve students’ critical thinking and metacognitive skills. The seven-lesson course teaches students how to assess risks, spot thinking errors like confirmation bias, evaluate sources of information, and understand the history of infectious diseases. The pilot program was tested in seven high schools, with measurements taken before (n = 512), immediately after (n = 124), and one month after the program (n = 107). We suggest that improving metacognition—helping individuals recognize the limitations of their own knowledge—is an important strategy to address vaccine hesitancy, particularly among those with moderate rather than extreme anti-vaccine attitudes.