Non-government organisations (NGOs) have long played a role in delivering sanitation services to communities in Southeast Asia and Pacific countries, particularly in rural areas. In contrast with large scale infrastructure focused initiatives, NGO programs commonly focus on building linkages between technical and social realms. Drawing on the breadth and depth of NGO experiences, there are opportunities for NGOs to play a greater role in the sanitation sector and to work in partnership with other actors including utilities and government agencies to ensure both 'hardware' and 'software' components of sanitation are built in to project design and delivery to maximise community benefits and ensure longer term system sustainability. This paper discusses these issues and considers how the contribution of NGOs to the sanitation sector in developing countries might be enhanced. The paper is based on recent research for the Australian Agency for International Development (AusAID) intended to guide investment in the water and sanitation sectors of Asia and Pacific partner countries, exploring the potential for increased NGO engagement. The paper presents findings of the research concerning NGO roles and approaches, discusses existing NGO activities in the sanitation sector in Vietnam and Timor Leste and identifies strategies for NGOs and for other sector actors including utilities and government agencies to maximise the benefits of NGO engagement in the sanitation sector.