Innovation is playing an increasingly transformative role across the humanitarian system. International organisations, NGOs, governments, business, military, and community-based organisations are drawing upon the language and methods of innovation to address the challenges and opportunities of a changing world. At the Humanitarian Innovation Project, we are developing the concept of bottom-up innovation, in order to introduce an alternative way of thinking about the role of innovation in the humanitarian sector. Rather than only considering how innovation can help international aid agencies to be more adaptable and effective, a focus on bottom-up innovation aims to enable aid agencies to support the creativity and skills of affected populations. Bottom-up innovation can be defined as the way in which crisis-affected communities themselves engage in creative problem-solving, finding solutions to their own challenges. This brief provides selected findings from our research in Uganda, Kenya, South Africa, Jordan, and the United States.