AbstractThe Geneva Convention relative to the Protection of Civilian Persons in Time of War provides a practical and effective framework for the protection of civilians in international armed conflicts that has retained its relevance for 75 years since its adoption. As with all treaties, its ‘object and purpose’ has a concrete impact on how its terms are interpreted, giving insights into the ordinary meaning of the text and allowing the aim of the Convention to be fully realized. This article asks and answers a series of questions to elucidate the role of the object and purpose in treaty interpretation and how to identify the object and purpose of a given treaty before focusing on the specificities of international humanitarian law treaties. On that basis, it determines that the overall ‘object and purpose’ of the Convention is to protect civilians during armed conflict, including in circumstances where they are subject to permissible measures of control and security. The article then demonstrates how that ‘object and purpose’ assists with the resolution of specific, well-known interpretive dilemmas including the determination of protected status under the Convention and the application of provisions premised on the existence of a Protecting Power.