Participatory budgeting programmes are spreading rapidly across the world because they offer government officials and citizens the opportunity to engage each other in new ways as they combine democratic practices with the ‘nitty gritty’ of policy-making. The principles and ideas associated with participatory budgeting appeal to a broad spectrum of citizens, civil society activists, government officials and international agencies, which helps explain why it is so popular and has expanded so quickly. This research briefing looks at how participatory budgeting is transforming in countries where international donors are active, where states struggle to provide public services, and where urban and rural communities are characterised by high levels of poverty. A workshop, held in Kenya, July 2017, brought together professionals from non-governmental organisations (NGOs) affiliated with the Making All Voices Count research programme, based in Indonesia, Kenya, Mozambique, the Philippines, Senegal, South Africa and Uganda. This enabled the identification of key transformations and adaptations in the participatory budgeting field. Key themes in this paper: participatory budgeting; adoption and transformation of practice in participatory budgeting over time; social justice and redistribution of resources.