This report describes a study of the dynamic between selected reform support organizations (RSOs) and the school districts they have partnered with to promote educational reform. The report is directed toward the needs and interests of district leaders and was designed to help them understand district/RSO relationships so they can make informed decisions about collaborating with external organizations. The study examined why districts choose to partner with an RSO, the nature of the engagement, expectations, interim results, key factors in the development of a relationship that promotes change, and elements of the interaction that lead to sustainable improvement. A total of 24 organizations were profiled (profiles are available at http://www.schoolcommunities.org/portfolio). Five of those organizations are reviewed in this report. The report begins with a discussion of the nature of relationships between RSOs and districts, followed by brief profiles of the collaborative effort between the district and RSO. The findings are then discussed and are followed by a set of practical questions to ask about partnerships with external organizations. The report concludes with some brief suggestions about possible lines of further inquiry. (Contains a list of 37 references and resources.) (WFA)