The use of big data promises to drive economic growth and development and can therefore be a value-adding factor, but compared to private or public organisations, the country level is rarely investigated, and that is even more evident for developing countries. Another topic hardly ever considered in the big data research field is ‘big data readiness’, which means the level of preparation and willingness to exploit big data. We address these shortcomings in the literature and focus on the big data readiness of developing countries. Thus, the first research question is: what components are required for an index measuring big data readiness, and how can such an index be designed? We use a design science approach to develop the “Big Data Readiness Index” (BDRI), which is then applied to all African countries to answer our second research question: how do African countries perform in terms of the BDRI? Our analysis yields country rankings that show relatively high BDRI scores for coastal countries, such as South Africa, Kenya and Namibia, and for islands, such as Mauritius. Related implications for both research and policy are discussed.