The purpose of this systematic review was to (1) conduct the systematic search of the literature to identify the studies on partnerships in school leader preparation; and to (2) systematically review the findings of these studies and synthesize them into major themes reflecting the state of the art in collaborative leadership preparation in the United States. Descriptive themes focused on the reasons for universities and school districts to collaborate; the content of collaborative leader preparation programs; the practitioners' involvement; factors to success; implementation barriers and successes; and the lessons learned. Reflections on the collaborative approach to principal preparation are provided.