In this paper we introduce an area of activity that has flourished for decades in all corners of the globe, namely grassroots innovation for sustainable development. We also argue why innovation in general is a matter for democracy. Combining these two points, we explore how grassroots innovation can contribute to what we call innovation democracy, and help guide innovation so that it supports rather than hinders social justice and environmental resilience.

Drawing upon qualitative case studies from empirical domains including energy, food, and manufacture, we suggest it does so in four related ways:

1. Processes of grassroots innovation can help in their own right to cultivate the more democratic practice of innovation more generally.
2. Grassroots innovations that result from these processes can support citizens and activities in ways that can contribute to practice of democracy.
3. Grassroots innovations can create particular empowering sociotechnical configurations that might otherwise be suppressed by interests around more mainstream innovation systems.
4. Grassroots innovations can help nurture general levels of social diversity that are important for the health of democracy in its widest political senses.

The paper finishes with a few suggestions for how societies committed to innovation democracy can better support and benefit from grassroots activity, by working at changes in culture, infrastructure, training, investment, and openness.

This is a peer-reviewed publication building on an earlier working paper, Grassroots Innovation and Innovation Democracy (STEPS Working Paper 89) and an earlier think piece commissioned by Friends of the Earth by the same authors.