Assault-related injuries in youth are associated with poor outcomes related to physical and mental health. These youth often seek acute injury-related care in the emergency department (ED), making this an important location for violence prevention and intervention efforts. This scoping review sought to describe ED-initiated and ED-based interventions for youth with assault-related injury. We searched 6 databases from their inception to October 2023: Ovid MEDLINE, Cochrane Library, Embase, Web of Science, PsycInfo, and CINAHL. We included original research on interventions for youth (0 to 18 years) presenting to the ED with assault-related injury (including firearm-related injury). We excluded non-English studies, conference proceedings, and editorials. Two independent reviewers performed title and abstract screening, full text review, and data abstraction and synthesis. We found 5,021 unique articles and excluded 4,955 after the title and abstract screening. The remaining 66 articles underwent full text review, and 25 were included. The primary types of ED interventions identified were case management, behavioral and psychosocial interventions, and mentorship. Although all interventions were initiated in the ED, the majority primarily occurred following discharge, required high levels of resources, and were often performed by hospital-based personnel in partnership with community-based organizations. Most studies described outcomes related to injury recidivism, criminal justice involvement, violence-related risk factors, health care usage, and mortality. Few described strengths-based and other quality-of-life outcomes. Although many studies demonstrated improved outcomes with interventions, they were often limited by sample size, study attrition, and short-term follow-up. Overall, our findings indicate that current research on ED interventions for youth with assault-related injuries is skewed toward resource-intensive services such as hospital-based violence intervention programs. Further work is needed to develop, implement, and rigorously evaluate community-informed ED-based interventions that could complement these resource-intensive interventions. Future studies should also examine strengths-based and patient-centered outcomes.