Findings from research on how clinically tested MST can be transported into real-world drug abuse and mental health treatment show the importance of the cultivation of the therapist, treatment supervisor, and consultation. The effectiveness of the transport of evidence-based MST into the delivery setting and the subsequent adherence of therapists to the proven methods of delivery has been shown to be a consistent predictor of short-term and long-term outcomes in such settings. The clinician and organizational factors also affect adherence and outcomes. Currently, the MST transport strategy, as implemented by MST Services and its 15 network partners reaches approximately 17,300 youths in 32 States and 10 countries per year. As the number of network partners increases, it will be possible to improve the design and implementation of the multicomponent strategy used to cultivate expertise in providing training and ongoing consultation to MST therapists and supervisors. Components of the MST transport strategy are a systematic site assessment process that determines the suitability of the site for MST implementation, training and ongoing support at multiple levels of program design and delivery, measurement of the fidelity of implementation at multiple levels, and outcome measurement. The article's description of the validation of the MST transport system addresses the conceptual framework, program development, and quality assurance and improvement protocols. 1 figure and 58 references