Cognitive and behavioral theories of Obsessive-Compulsive Disorder (OCD) and related disorders (e.g., Body Dysmorphic Disorder [BDD] and tic disorders) have led to the development of effective treatments, although clinically significant outcomes are not consistent and both dropout and relapse rates remain high. Researchers have turned to alternative theoretical frameworks to advance our understanding of these disorders and to provide novel insights into either new interventions or the tailoring of existing interventions. Neuroscientific evidence from neuropsychological, functional and structural imaging, and electrophysiological studies has implicated the role of frontal-striatal dysfunction in OCD and related disorders. However, to date, neuroscientists and cognitive-behaviorists have tended to publish in separate journals, with few attempts at integrating their respective evidence bases to advance understanding of psychopathological processes, or in progressing knowledge of treatment-related processes. This special edition presents four articles on OCD and related disorders which present results from studies integrating neuroscientific and cognitive-behavioral approaches, methodologies, and measures. This introduction to the special edition outlines some of the background of this initiative, and contextualizes the articles.