Children obtain more mental health services through schools than through any other system. In urban, low-resource schools, mental health care often is provided by teams of contracted community mental health workers. Implementation of intended services may struggle in the context of challenges related to team functioning. Team Strategies and Tools to Enhance Performance and Patient Safety (TeamSTEPPS) is an efficacious approach for improving team functioning in health care. In collaboration with stakeholders, we adapted TeamSTEPPS for school mental health teams and pilot-tested it in 3 schools participating in an ongoing implementation of cognitive-behavioral therapy. In total, 3 teams randomized to receive TeamSTEPPS were compared with 3 teams who did not participate in TeamSTEPPS. Feasibility and acceptability of the adapted TeamSTEPPS and the impact on team skills and behavior were assessed through qualitative interviews and field notes and quantitatively over the course of 1 school year. In this article, we describe the process of adapting and implementing TeamSTEPPS. In addition to providing the researchers' perspective, we illustrate participant perspectives using qualitative data when possible. Key challenges included leader and staff turnover, logistical barriers (e.g., difficulty securing private space for qualitative interviews in schools), and navigating the protection of participant rights and autonomy given that prospective participants were employed by an agency with a vested interest in their participation. Concrete suggestions for overcoming challenges are provided to guide future research. (PsycINFO Database Record (c) 2019 APA, all rights reserved).