The present chapter investigates the civilian function of dual-use objects, a concept that has been often mentioned, without ever delving into its significance, nor into its practical implications. The analysis moves from the assumption that what makes an object more, or less, valuable than others boils down to the civilian function that it plays, especially in the context of an armed conflict. Function is defined by the Oxford English Dictionary as “an activity or mode of operation that is proper or natural to a person or thing, the purpose or intended role of a thing” and, despite not being a term of art in the legal sense, it is not alien to the IHL framework. Several authors over the years have noted how governments are uncomfortable with the notion that the civilian function of a dual-use facility can be so easily ignored in armed conflicts, yet efforts to fully and adequately take into account said function have been scant, if any. After reflecting on the civilian function of dual-use objects, the present chapter will provide a long overdue analysis that aims at finally reconciling this essential feature of dual-use objects with the relevant IHL rules and with the main principles of IHL.