Implementing a psychotherapy trial presents difficulties to even the most seasoned clinical researchers. Implementing a psychotherapy trial in the context of eating disorder (ED) patients presents inherent additional challenges, particularly in a group context. In this chapter, we reflect on and share key lessons learned from implementing a multisite trial of group schema therapy (ST) for EDs. We believe these lessons will have clear implications for those seeking to implement similar schema group programs, and include coverage of some key issues that arose from the assessment phase, through to therapy implementation and follow-up.