The difference between the potential yield and the actual yield of maize (yield gap) shows great spatial differences in Africa. nOn average in Africa, a small yield-gap is correlated with good market access as well as a high use of fertiliser. However, this result varies spatially when looking at more detailed spots. In many regions in Africa, large and small yield-gaps are correlated with good and deficient market access and/or high and low fertiliser use. The distinct regions are often demarcated by administrative boundaries, suggesting a political-institutional dimension with respect to the causes of yield gaps.