 This paper provides an overview of the current state of implementation outcomes research. It shows that most studies have focused on acceptability, fidelity, feasibility, adoption, and appropriateness, but there is still much work to be done in terms of understanding the relationship between implementation strategies and implementation outcomes. Additionally, few studies have looked into the impact of implementation outcomes on other important outcomes, such as service system and improved individual or population health. This article was authored by Enola K. Proctor, Alicia C. Bunga, Rebecca Lengnicall, and others.