Over the past eighteen years, research into test-enhanced learning has expanded significantly and remains vibrant to this day. The fact that many major research questions in the literature have already been addressed, however, raises the question: “What’s next?” That question motivates this special issue. We asked leading researchers in the field to contribute articles highlighting cutting-edge and new directions in test-enhanced learning research. The resulting review papers, empirical articles, and commentaries address many fascinating topics, including: (a) new approaches that are generating insights into test-enhanced learning in relation to other learning techniques (e.g., combining testing with elaborative or generative learning activities); (b) investigations of lesser-known test-based learning strategies that have the potential to enhance educational outcomes (e.g., pretesting and prequestioning, spaced retrieval practice, test-potentiated new learning or forward testing; and successive relearning); (c) new research on effective uses of practice testing during self-regulated learning and in other contexts; and (d) how to promote awareness and acceptance of test-enhanced learning among students and practitioners. These articles showcase some of the most promising new directions in test-enhanced learning research, so we anticipate that this special issue will inspire further investigations of practice testing and its educational applications.