This commentary evaluates the accomplishments of research on metacognitive therapy (MCT) featured in the Special Issue on this topic. It begins with an overview of key features of MCT and highlights its basis in information-processing theory. A summary of the contributions to the Special Issue demonstrates that contemporary research supports both the theoretical principles and clinical effectiveness of MCT. Several challenges will remain as MCT becomes further established as a therapy of first recourse for a range of emotional disorders. At a theoretical level, more fine-grained understanding of the temporal dynamics of specific attentional processes is needed, as well as investigation of implicit processing. For clinical application, larger scale trials of the effectiveness of MCT in comparison with other therapies are needed. Progress in meeting these challenges is expected as the benefits of MCT become more widely-known.