This document discusses the key implementation challenges for the post-2015 development agenda. It begins by setting the scene on what may change in the post-2015 framework compared to the MDGs, including a more inclusive process, focus on structural transformation, and addressing growing inequalities. It then examines case studies of ongoing transformation processes and challenges in Tunisia, Ethiopia, and Ukraine. The main implementation challenges identified are: recognizing complexity in socio-economic and political systems requiring experimental approaches; balancing global goals with national ownership; using multi-actor approaches requiring negotiation; applying the subsidiarity principle with local implementation; requiring integrated, coherent approaches across sectors; shifting from financial aid to knowledge exchange; developing accountability frameworks through inclusive processes; and overha