Integrated river basin management (IRBM) calls for participatory practices involving stakeholders along transnational river landscapes. Understanding the complex and diverse views regarding participation is a prerequisite for meaningful involvement of civil actors, especially in a transnational context. In a case study along the Lower Rhine river, we assessed and compared cognitive perceptions towards IRBM of citizen initiatives and nature organizations from Germany and the Netherlands and their previous experiences with participation processes.We found large differences between the four actor groups in motivations to participate as well as in levels of trust towards institutions. This study also showed different views on participation between the two countries with regard to the problem definition, nature images and the perceived relationships between government organisations on the one hand and citizen initiatives and nature organisations on the other hand.The findings suggest that views vary between citizen initiatives and nature organizations within a country and that cultural notions add to the complexity of transnational participation. In transnational participation processes, the varying views between actor groups should be taken into account, as well as the complexities among countries even within actor groups.