This article studies civil–military relations in defence procurement. Applying insights from the principal–agent model, we argue that decision-making about defence procurement is inherently vulnerable to agency problems. Given the technical nature of these dossiers, governments and parliaments are often heavily dependent upon military expertise, creating leeway for defence administrations to steer decision-making towards their preferences. By means of a case study of the replacement of the F-16 fighter jets in Belgium, we examine whether and how complex defence procurement dossiers allow for exploitation of expertise through strategic information management from the defence administration to the Minister of Defence. In addition, empirics reveal a to date unexplored phenomenon of agent intrusion. It captures the situation in which an agent takes a prominent formal advisory position within the decision-making apparatus of its political principal, providing additional means to outplay its information advantage over the principal in favour of its own interests.