Conflict is one of the most fundamental concepts in the interest group literature. The more conflict there is, the less likely it is that interest groups can impact policymaking. In this paper we systematically explore whether some types of conflict affect interest-group influence more than others. More precise whether conflict among organizations that are perceived by policymakers as homogenous (‘internal conflict’) is more detrimental for the influence interest groups have on policymaking than conflict among groups that are not perceived by policymakers as homogenous (‘external conflict’). Empirically we focus on four cases of EU policymaking with varying levels of internal and external interest group conflict. Our case studies highlight that agreement among similar types of lobby organizations is a necessary condition for these groups to influence policymaking, while external conflict still provides much opportunities for interest groups to influence policymaking.