Background: School mental health care often is provided by teams contracted from community mental health agencies. The team members that provide this care, however, do not typically receive training in how to work effectively in a team-based context. Team Strategies and Tools to Enhance Performance and Patient Safety (TeamSTEPPS) provides a promising, evidence-based strategy for improving communication and climate in school-based teams. Methods: In collaboration with stakeholders, we adapted and piloted TeamSTEPPS for use with school mental health teams. Teams in six schools were randomized to receive the adapted TeamSTEPPS approach or usual supports. The main outcomes of interest were feasibility and acceptability of the adapted TeamSTEPPS strategy. Results: Results indicated that team member burnout was significantly higher at follow-up than pretreatment for both control and intervention teams. TeamSTEPPS was feasible and acceptable to implement, and leadership emerged as an important facilitator. Barriers to implementation success included staff turnover, lack of resources, and challenges in the school mental health team relationship. Additional supports to implement TeamSTEPPS were suggested, including ongoing consultation and booster training to address high staff turnover. Conclusions: Results suggest that TeamSTEPPS is promising for school mental health teams but additional modifications are likely needed.