States and districts are under increased pressure to turn low-performing schools around. In this paper, we review research on how experienced external partners and experts can help move low performing schools through their reform process and leave them on a path to true turnaround. We found that external partners should be brought in to play one or more of three specific roles: (1) Provide deep knowledge of what really helps low-performing schools change their performance trajectory; (2) Provide additional capacity and resources to already stretched-thin schools; and (3) Bring a thorough understanding of how to actually make change happen, based on previous experience in other school and district settings. The paper elaborates on these strategies, and describes how external partners have helped turnaround schools in Boston, Massachusetts.