Around the world, civil society organisations (CSOs) and governments are experimenting with information communication technology (ICT) platforms that try to encourage and project citizen voice, with the goal of improving public service delivery. This paper reviews evidence on the use of 23 information and communication technology (ICT) platforms to project citizen voice to improve public service delivery. This meta-analysis focuses on empirical studies of initiatives in the global South, highlighting both citizen uptake (‘yelp’) and the degree to which public service providers respond to expressions of citizen voice (‘teeth’).