We examine the degree to which party leaders dominate their parties over time and across countries and analyse how leadership domination relates to formal aspects of party organisation. Moreover, we analyse whether antidotes against leadership domination – widening the selectorate and increasing the membership – explain change in leadership domination. For this purpose, we use a new dataset that brings together different sources of party data over time and between countries. We find that leadership domination indeed has increased over time, but still a lot of variation exists between parties. We also demonstrate that widening the selectorate – for example, letting members elect the party leader – and increasing membership boosts leadership domination. In other words, the antidotes against leadership domination do not work.