Workplace-based assessment (WBA) serves a critical role in supporting competency-based medical education (CBME) by providing assessment data to inform competency decisions and support learning. Many WBA systems have been developed, but little is known about how to effectively implement WBA. Filling this gap is important for creating suitable and beneficial assessment processes that support large-scale use of CBME. As a step toward filling this gap, the authors describe what is known about WBA implementation and use to identify knowledge gaps and future directions. The authors used Arksey and O'Malley's 6-stage scoping review framework to conduct the review, including: (1) identifying the research question; (2) identifying relevant studies; (3) study selection; (4) charting the data; (5) collating, summarizing, and reporting the results; and (6) consulting with relevant stakeholders. In 2019-2020, the authors searched and screened 726 papers for eligibility using defined inclusion and exclusion criteria. One hundred sixty-three met inclusion criteria. The authors identified 5 themes in their analysis: (1) Many WBA tools and programs have been implemented, and barriers are common across fields and specialties; (2) Theoretical perspectives emphasize the need for data-driven implementation strategies; (3) User perceptions of WBA vary and are often dependent on implementation factors; (4) Technology solutions could provide useful tools to support WBA; and (5) Many areas of future research and innovation remain. Knowledge of WBA as an implemented practice to support CBME remains constrained. To remove these constraints, future research should aim to generate generalizable knowledge on WBA implementation and use, address implementation factors, and investigate remaining knowledge gaps.