In this review, we examine common usage of the term "third wave" in the scientific literature, systematically review published meta-analyses of identified "third wave" therapies, and consider the implications and options for the use of "third wave" as a metaphor to describe the nature of and relationships among cognitive and behavioral therapies. We demonstrate that the "third wave" term has grown in its use over time, that it is commonly linked with specific therapies, and that the majority of such therapies have amassed a compelling evidence base attesting to their clinical and public health value. We also consider the extent to which the "third wave" designation is an effective guide for the future, and we encourage scientific inquiry and self-reflection among those concerned with cognitive and behavioral therapies and the scientific basis of psychotherapy more broadly.