Over the course of a 5-year applied research project with more than 1,400 middle school students, evidence from a number of studies revealed that retrieval practice in authentic classroom settings improves long-term learning (Agarwal et al. 2009; McDaniel et al., "Journal of Educational Psychology" 103:399-414, 2011; McDaniel et al. 2012; Roediger et al., "Journal of Experimental Psychology: Applied" 17:382-395, 2011a). Retrieval practice, or the use of quizzes and exams to engage and enhance retrieval processes, has been widely established as an effective strategy for facilitating learning in laboratory settings (e.g., Roediger et al. 2011c). In this article, we review recent findings from applied research that demonstrate that retrieval practice enhances long-term classroom learning, delayed quizzes are particularly potent for retention, quizzes benefit students' transfer to novel quiz items, and quizzes with feedback improve students' learning and metacognitive awareness. In addition to generating evidence to support retrieval-based learning, these applied research studies also enhanced the professional development of the teachers, administrators, and scientists involved in the project. In this article, it is our hope that by sharing what we have learned from a variety of perspectives, applied scientific research in K-12 classrooms will continue to be explored and generated at local, state, and national levels, improving student learning and educational decision-making.