This thesis studies the legal significance of the status of party to the conflict in international humanitarian law, by assessing under which conditions an entity can be considered party to a conflict and which entities have the capacity to become so. Part I deals with the legal framework applicable to the status of party to the conflict, tracing its development in the drafting history of international humanitarian law by combining a textual interpretation of the provisions with a study of the intentions of the drafters in light of the historical context. Part II of the thesis assesses the applicability of the status of party to the conflict to contemporary situations. In particular, Chapter 1 of Part II proposes an evolutionary interpretation of the features and significance of the status of party to the conflict, fleshing out the requirements that an entity needs to have to be considered party to a conflict. Such clarification is instrumental to the following analysis of the potential applicability of the status to entities such as international organizations and private military and security companies. Chapter 2 of Part II engages with the different ways in which the role of party to the conflict is interpreted by different entities, highlighting the most relevant aspects that are raised by each case study. On the basis of the working definition of party to the conflict emerged from the analysis, Chapter III of Part II takes a normative position on the scope of the status, reflecting on the effects and consequences of a potential broadening of its scope of application.