The crafting of the post-2015 development agenda began with a pivotal decision, taken at the Rio+20 conference, to integrate environmental, social, and economic issues into a set of sustainable development goals (SDGs). Since their inception, the Millennium Development Goals (MDGs) have become a unifying mechanism for a previously disjointed development community, but their narrow focus excluded coalitions advocating that greater attention be paid to environmental issues and transformative economic growth. The SDGs are being developed as objectives that are both universal (applying to all countries) and comprehensive (cutting across most sectors). This article contrasts the creation process of the MDGs with the current process to reach an agreement on the SDGs, reviewing the ensuing tensions and debates. It describes key lessons from the MDG experience over the past fifteen years and outlines the shifts that are necessary for a successful post-2015 framework.