Based on research and interviews with policy and field staff of 12 large international development NGOs, this paper draws out cross-agency learning on building institutional capacity for conflict-sensitive practice. Lessons regarding organisational development are identified with emphasis on commitment and motivation, organisational culture, capacity building and accountability and external relationships. The report concludes, amongst other things, that peacebuilding should not be seen as a separate, technical activity but should be integrated into development and humanitarian programming. It also stresses the need for strengthened cross-programme learning and closer relationships between humanitarian/development organisations and research, advocacy and human rights agencies.