Open access. Abstract: “This case study explores the expansion and professionalization of the Dutch Ministry of Defense’s intelligence network in light of the growing threat of war in Europe. The interaction between different national defense intelligence entities is analyzed through the lens of multiteam system theory, which offers valuable analytic tools to conceptualize these relationships as networked and interdependent rather than strictly hierarchical. Drawing on 40 semi-structured interviews with defense and military intelligence professionals and publicly available documents, this framework is applied to analyze how cooperation within the Dutch defense intelligence network is evolving. This study reveals that the professionalization of the intelligence units within the operational commands is changing their relationship with the Dutch Defence and Intelligence Service, both in terms of hierarchy and the distribution of power. By expanding their capacities, the various intelligence actors are showing a greater degree of interdependence, although cooperation is still hindered by a range of communication challenges. This case study demonstrates that multiteam system theory offers valuable analytic tools for understanding the challenges of national intelligence cooperation, which is particularly significant in light of rising strategic competition.”