While serving as USAID’s Social Movements Advisor I researched and wrote this Primer on Nonviolent Collective Action in Democratic Development. It is a reference tool for USAID personnel, partners, and the public interested in deepening their understanding of social movements, grassroots organizing, and other forms of nonviolent collective action. Around the world, attacks on civic space and changes in how people are using nonviolent collective action have altered the effectiveness of nonviolent collective action and how donors such as USAID can support it. Yet, it remains a core strategy of civic participation for people around the globe. Therefore this primer also explores new opportunities and challenges USAID and its partners face when considering whether, when, where, and how to support nonviolent collective action. It is a document that was cleared for public use and I share it here in the same spirit.