School psychology training programs take great pride in claiming to prepare scientist-practitioners consistent with the tradition of the Boulder model. Science as a basis for practice is also endorsed by government initiatives, such as in the case of Individuals with Disabilities Education Act of 2004 and No Child Left Behind Act of 2001, in which research-based interventions became codified into law as the standard of practice. Moreover, the American Psychological Association recommended that evidence-based interventions (EBIs) be prioritized for all psychological services. Despite these efforts, many school psychologists find their practice influenced less by science and more by case law, legislation, regional and local regulation, tradition, standards set by eminent scholars and practitioners, and other factors unrelated to science. Although there are a host of EBIs available in nearly all professional fields, the implementation of EBIs is not especially common, given the many obstacles EBIs face when it comes to real-world implementation. Embracing and implementing EBIs is an important shift toward professionalism and responsiveness to the needs of children, families, and schools; yet implementation remains a challenge. The emphasis on EBIs is a useful step in establishing school psychology as a profession that provides demonstrable outcomes based on scientific principles. However, the danger is in the belief that EBI is the final destination in the development of a strong scientist-practitioner practice in the tradition of the Boulder model. EBI is a necessary, but not sufficient step. The next step involves implementation science. Implementation science is the study of methods to promote the integration of research findings and evidence into policy and practice. Knowing what works is essential; it is also critical to know how, where, when, why, and or whom do innovative practices work. The interdisciplinary field of implementation science has the potential to answer these questions and to comprise a new wave of research that will lead the implementation of innovations in education and psychology.