Hereditary leadership has been an important feature of the political landscape throughout history. This paper argues that hereditary leadership is like a relational contract which improves policy incentives. We assemble a unique dataset on leaders between 1874 and 2004 in which we classify them as hereditary leaders based on their family history. The core empirical finding is that economic growth is higher in polities with hereditary leaders but only if executive constraints are weak. Moreover, this holds across of a range of specifications. The finding is also mirrored in policy outcomes which affect growth. In addition, we find that hereditary leadership is more likely to come to an end when the growth performance under the incumbent leader is poor.