Knowledge is an essential determinant and component of the international development cooperation agenda and projects. Therefore, it is vital to understand and reflect on how knowledge in international development cooperation is created, what knowledge counts, and how it influences the planning, implementation, and outcomes of international development cooperation projects. In this paper, we critically examine the knowledge system of the development cooperation of the Czech Republic, an emerging donor country, by applying system theory and utilizing system properties as an analytical tool. To this end, we carried out a multi-phase qualitative research with actors from the Czech Republic and Zambia. Subsequently, we analysed the knowledge system properties and identified those often overlooked by development actors, such as taboos, mistrust, and development burden, revealing how knowledge flows can be obstructed by these characteristics. In addition, we compiled a set of suitable interventions to tackle the overlooked system properties and foster knowledge cross-fertilisation. These interventions include, among others, active engagement of traditional leaders, active work with narratives of success, and introducing action-reflection-reaction cycle into the development practice. Furthermore, the proposed interventions clearly emphasize the need for more collaborative and transdisciplinary processes. Finally, we discuss that it is essential to uncover deep layers of the international development cooperation knowledge system to shift and leverage it towards more inclusive and just outcomes.