The recently-released "College, Career, and Civic Life (C3) Framework for Social Studies State Standards" proposes an "inquiry arc" organized around developing questions and planning inquiries, applying disciplinary concepts and tools, evaluating sources and using evidence, and communicating conclusions and taking informed action. There are many ways to take informed action, including by writing editorials, leading an activity for younger students, curating an exhibit, or creating and sharing media. In this article, associate professor Meira Levinson draws attention to one ambitious but exciting way to foster students' capacities to take informed action: namely, through action civics. Herein, she defines action civics and explains how it works. She goes on to discuss the reasons why action civics empowers youth and what supports teachers need in place to transform their own teaching and students' learning, engaging everyone in Taking Informed Action as an essential, motivating, and deeply educational culmination of the C3 Inquiry Arc.