UNAIDS Cosponsors and the Secretariat have prepared this document focused on critical enablers and development synergies as an additional component to existing guidance. The purpose of this document is two-fold: (1) to elaborate on the concepts of critical enablers and development synergies and (2) to demonstrate why and how they are necessary components of national AIDS responses. The audience is broad and includes, but is not limited to: planners and implementers of basic programme activities and critical enablers; development sectors (including government and civil society partners within and outside of health sector) who wish to understand how their core business can affect HIV outcomes; and international and national financing institutions that invest in HIV, health and/or development. This document is organized around two themes: defining critical enablers and development synergies: why they matter and how they interact for HIV outcomes; and implications for financing and governance.