Health inequalities represent perhaps the most consequential global health challenge and yet they persist despite increased funding and innovative programs. The United Nations is revising the Millennium Development Goals (MDGs) that will shape the world for many years to come. What would a transformative post-MDG framework for global health justice look like? A global coalition of civil society and academics--the Joint Action and Learning Initiative on National and Global Responsibilities for Health (JALI)--has formed an international campaign to advocate for a Framework Convention on Global Health (FCGH). Recently endorsed by the UN Secretary-General, the FCGH would reimagine global governance for health, offering a new post-MDG vision. This Special Communication describes the key modalities of an FCGH to illustrate how it would improve health and reduce inequalities. The modalities would include defining national responsibilities for the population's health; defining international responsibilities for reliable, sustainable funding; setting global health priorities; coordinating fragmented activities; reshaping global governance for health; and providing strong global health leadership through the World Health Organization.