Background: Multistakeholder alliances that bring together diverse organizations to work on community-level health issues are playing an increasingly prominent role in the U.S. health care system. Yet, these alliances by their nature are fragile. In particular, low barriers to exit make alliances particularly vulnerable to disruption if key stakeholders leave. What factors are linked to the sustainability of alliances? One way to approach this question is to examine the perceptions of alliance participants, whose on-going involvement in alliances likely will matter much to their sustainability. Purpose: This study addresses the question: "Under what conditions do participants in alliances consider that their alliances are well positioned for the future, will perform well over time, and will be able to deal effectively with future challenges?" Methods: We draw on cross-sectional survey data collected in the summer of 2015 from a total number of 638 participants in 15 alliances that participated in the Robert Wood Johnson Foundation's Aligning Forces for Quality program. Results: Results from regression analyses indicate that alliance participants are more likely to view their alliances as sustainable when they (a) share a common vision, goals, and strategies for the alliance and (b) perceive that the alliance has performed effectively in the past. Practice Implications: Leaders of multistakeholder alliances may need to ensure that alliances are collective efforts that build success one step at a time: to the extent that participants believe they share a vision and strategies and have had some prior success working together, the more likely they are to view the alliance as sustainable.