Annex for the CoST Public Private Partnership (PPP) Learning Paper. This paper explores the lessons learnt from CoST Honduras’s work heightening transparency, participation and accountability in PPP projects. This led to important project and sectoral change, preventing an unsustainable project from moving forward and contributing to institutional reform. As this note shows, transparency and independent scrutiny is of vital importance to avoid the pitfalls and ensure the potential of PPP projects. Lessons from the Honduras experience can be used by others to avoid mistakes from early stages and rapid acceleration of PPP projects.