This paper focuses on the Incredible Years Teacher Training (IY TT) intervention as an example of an EBP that embeds fidelity and adaptation within its design. First, the core features of the IY TT program along with the methods and processes that make the intervention effective are described. Second, the support mechanisms (training, mentoring, consultation, and IY TT coaching) necessary to facilitate high fidelity of implementation of IY TT are highlighted. The goal is to clarify the underlying principles and layered supports needed to effectively disseminate the IY TT program to audiences with diverse backgrounds and skills who work with students with varying developmental, academic, and social-emotional needs. Often fidelity and adaptation are thought of as mutually exclusive, but in the IY model they are considered both complementary and necessary. Implications for school psychologists and prevention science are discussed.