This brief is part of a series that explores key implementation considerations. It focuses on the importance of identifying, operationalizing, and implementing the "core components" of evidence-based and evidence-informed interventions that likely are critical to producing positive outcomes. The brief offers a definition of "core components", discusses challenges and processes related to identifying and validating them, highlights rationales for the importance of operationalizing core components, and explores implications for selecting, funding, implementing, scaling up, and evaluating programs. Since the issues related to core components of interventions are relevant to producing new knowledge about what works and for moving science to service in socially significant ways, this brief is relevant for a range of professionals and stakeholders, including program developers, researchers, implementers, and policy makers. (Contains 1 table and 2 figures.)