The Evaluation of the Enhanced Collaborative Model (ECM) to Combat Human Trafficking study was the first federally funded, multisite, mixed-methods study on ECM task forces in the United States. This brief documents findings on the collaboration between key ECM task force stakeholders and challenges to collaboration. Results from our study indicate that respondents perceive ECM task forces as instrumental in increasing collaboration across agencies, improving awareness about human trafficking, and enhancing system capacity to handle trafficking cases. Challenges include breakdowns in communication and coordination, staff burnout and turnover, personality differences, task forces that are siloed and too large, and differing processes and goals that limit productivity and effectiveness. Key recommendations from task force stakeholders to improve collaboration include enhancing organizational and operational factors, strengthening relationships between task force members, and leading more trainings and activities.