In this chapter, we focus on defining inquiry. We draw comparisons to other subject areas where inquiry is more well known, such as science. Additionally, we make the case for why inquiry should be an integral part of social studies education because it is crucial to developing civic reasoning and supporting our democratic society. Through inquiry, students develop decision-making skills, critical thinking, and the ability to form evidence-based arguments, which we believe are essential skills for citizenship. Furthermore, we argue that a primary purpose in inquiry-based social studies instruction is to develop independent inquiry skills. As such, a portion of this chapter will also focus on student-led inquiry.