Many governments, international agencies and civil society organizations (CSOs) support and promote open data. Most open government data initiatives have focused on supply - creating portals and publishing information. But much less attention has been given to demand - understanding data needs and nurturing engagement. This research examines the demand for open data in South Africa, and asks under what conditions meeting this demand might influence accountability. Recognizing that not all open data projects are developed for accountability reasons, it also examines barriers to using government data for accountability processes. The research team identified and tested ‘use stories’ and ‘use cases’. How did a range of civil society groups with an established interest in holding local government accountable use - or feel that they could use - data in their work? The report identifies and highlights ten broad types of open data use, which they divided into two streams: ‘strategy and planning’ - in which CSOs used government data internally to guide their own actions; and ‘monitoring, mobilizing and advocacy’ - in which CSOs undertake outward-facing activities.