Abstract Belgium was established in 1830 as a unitary state with a bicameral parliament, with symmetrical powers for the upper and the lower house. While federalism and bicameralism are often considered a pair, the Belgian system shows an inverse relationship. The Senate gradually turned into a house representative of the sub-states, but its powers declined inversely proportional to the level of decentralisation of the Belgian state. This paper inquires how the dismantling of the Belgian Senate fits in the increasingly devolutionary nature of the Belgian state structure. First, it nuances the link between bicameralism and federalism: bicameralism is an institutional device for federalism, but not by necessity, and only under specific conditions. The official narrative is that the Belgian Senate was reformed to turn it into a house of the sub-states in line as a federal principle, but in reality the conditions to fulfil this task are not fulfilled. Instead, the paper holds that bicameralism in Belgium is subordinate to the needs of multinational conflict management, and that complying with the federative ideal of an upper house giving voice to the collective needs of the sub-states would stand in the way of the evolution of the Belgian system towards confederalism based on two major linguistic groups.