The interplay between anxiety pathology and substance use disorders is increasingly recognized in empirical and clinical work. The present article serves as a general introduction to the special series highlighting the relationship between a number of anxiety conditions and a variety of substance use disorders. In this overview, we first discuss the importance of better understanding the association between anxiety and substance use and abuse followed by a brief review of each study and their major findings. This set of studies has implications for our understanding of the nature of these conditions as well as their treatment. We hope that this body of work will inspire future research in this important area.