• children's mental health;
  • dissemination and implementation research;
  • evidence-based treatments;
  • treatment integrity

This special series focuses upon the ways in which research on treatment integrity, a multidimensional construct including assessment of the content and quality of a psychosocial treatment delivered to a client as well as relational elements, can inform dissemination and implementation science. The five articles for this special series illustrate how treatment integrity concepts and methods can be applied across different levels of the mental health service system to advance dissemination and implementation science. In this introductory article, we provide an overview of treatment integrity research and describe three broad conceptual models that are relevant to the articles in the series. We conclude with a brief description of each of the five articles in the series.