The relationship between the state and traditional governance institutions (TGI) in contemporary politics has recently received increased scholarly attention. Traditional leaders play important roles in elections, public goods provision or conflict resolution in Sub-Saharan Africa. We analyse under what conditions cooperation or conflict emerge between the state and TGI. We contribute to the understanding of state-traditional relations by studying how governments interact simultaneously with varying TGI of different ethnic groups. We compare state-TGI relations for eight traditional polities in Kenya, Namibia, Tanzania, and Uganda, based on extensive fieldwork and interviews with state and traditional authorities, experts and constituents. We study three factors shaping state relations with different TGI: (1) the significance of TGI – both social and organisational – in each country and ethnic group; (2) the institutional similarity of TGI and state; and (3) the integration of TGI – both legal and political. Our analysis shows TGI with social significance and functional organisations challenge the state more frequently. Constitutional ambiguity fosters conflict between TGI and state. For our cases, relations are less conflictive in countries with more democratic governments. The same governments and TGI often simultaneously engage in cooperative and conflictive relations, highlighting that governments rarely pursue uniform policies with all TGI.