Many new initiatives for population health improvement feature partnerships of leaders and organizations across multiple sectors of society.

The purpose of this article is to review:

1. the rationale for such partnerships as an important, if not essential, tool for population health improvement;
2. key organizational and contextual factors that appear to be associated with effective multisector partnerships; and
3. the limited evidence regarding the effect of such partnerships on population health outcomes.

We conclude that systems thinking—accounting for the collective effect of many actors and actions—is essential to organizing and sustaining efforts to improve population health and to evaluating them. More research is needed to understand how and why multisector partnerships are formed and sustained and the conditions under which multisector partnerships are necessary or more effective than other strategies for population health improvement. Research on and evaluation of multisector partnerships also need to incorporate more standard measures of partnership contexts, characteristics and strategies, and adopt longitudinal and prospective designs to accelerate social learning in this area. Finally, studies of multisector partnerships must be alert to the value of such initiatives to individuals and communities apart from any direct and measurable impact on population health.

This article is part of a special supplement of Preventing Chronic Disease: Public Health Research, Practice, and Policy.