Public policy initiatives to deliver evidence-based practices in community settings have increased the need to develop implementation feedback systems to assist program administrators adopting the practices as well as researchers who wish to continue the line of research. This paper contributes to the efforts to reduce the implementation gap in the children’s mental health services field by exploring the concept of fidelity and highlights its importance to the adoption of evidence-based practices. Fidelity, or the degree to which interventions are implemented as originally designed, is generally conceptualized as a system of five unique and interrelated components including adherence, dosage, participant responsiveness, quality of delivery, and program differentiation. Definitions and a critical analysis of each of the component’s strengths and weaknesses are offered while discussing the integrated nature of each component. An example of the development and use of the five components of fidelity within a community-based evidence-based program is described.