In the last several years, a number of researchers have developed a transdiagnostic or unified group cognitive behavioral therapy (CBT) that is provided to a diagnostically heterogeneous group consisting of individuals with various anxiety disorders and/or depression. This article provides a review of recent developments within this transdiagnostic perspective to CBT. Three approaches to transdiagnostic CBT are considered that vary in their theoretical emphasis. At this time, the unified protocol for emotional disorders offers the most cogent theory-driven transdiagnostic treatment approach, although its efficacy has yet to be demonstrated. The advantages and challenges of transdiagnostic CBT are reviewed, and the article concludes with a proposal that future research on transdiagnostic CBT would be better served if viewed as complementary rather than antagonist to well-established manualized disorder-specific CBT for the anxiety disorders and depression.