In this article, we present the results of a cluster-randomized trial of an inquiry-based science curriculum conducted in grades 6-8 with 551 students in 13 schools. The intervention integrates science and civics instruction in a unit about community and family water conservation. The intervention also includes teacher professional development and technology-based tools to support instruction. We examined effects in science and civics, finding that student engagement in both areas was positively affected by the intervention. We argue that best practices in inquiry-based science instruction have value for students' civic development and that the integration of science and civics in the classroom can enhance student outcomes in both fields.