A structured interview survey of directors of a large national sample (n = 200) of mental health service organizations treating children examined the governance, financing, staffing, services, and implementation practices of these organizations; and, director ratings of factors important to implementation of new treatments and services. Descriptive analyses showed private organizations financing services with public (particularly Medicaid) funds are prevalent and that employment of professional staff, clinical supervision and training, productivity requirements, and outcomes monitoring are common. Results of random effects regression models (RRMs) evaluating associations between governance, financing, and organizational characteristics and the use of new treatments and services showed for-profit organizations more likely to implement such treatments, and organizations with more licensed clinical staff and weekly clinical supervision in place less likely to do so. Results of RRMs evaluating relations between director ratings of the importance to new treatment and service implementation of three factors-fit with existing implementation practices, infrastructure support, and organizational mission and support-suggest greater importance to public than private organizations of these factors. Implications for EST implementation and future research are described.