Abstract: This study compares the defence and national security of Belgium and the Netherlands. It shows a remarkable amount of parallel evolutions and events that shaped the securitization of the Netherlands and Belgium. Both countries faced many common security and defence challenges, which they dealt with in their own way but still at times very similar. Such comparison offers insight into how the proximity and similar development of the Low Countries provided a relatively common set of security contingencies and activities, and the differing or similar attitudes and responses both countries adopted towards common security problems. The internationally precarious situation of the two small countries caught in the middle between France and Germany exposed them to a similar threat. Their strategic location in Europe was also responsible for similar challenges in the domestic security environment, such as the threat of socialist agitation and later terrorism. These factors have influenced their international outlook as well as their legal and organizational approaches towards intelligence.