This article examines the international legal protections for United Nations humanitarian assistance and other civilian facilities during armed conflict, including under general international law, setting forth the immunities of the United Nations, and the law of armed conflict (LOAC), the relevant legal framework during wartime. Recent conflicts highlight three primary issues: (1) collateral damage to UN facilities as a consequence of strikes on military objectives nearby and military operations in the immediate vicinity; (2) the misuse of UN facilities for military purposes; and (3) direct attacks on fighters, weapons or other equipment that cause damage to such facilities. To identify the appropriate parameters for, and limits of, protection for such facilities, this article therefore focuses on what “inviolability” of UN premises—the term used in privileges and immunities law—means within the context of armed conflict and the law of armed conflict. Part Two of this article addresses the question of which law governs for the purposes of determining the scope of protection for UN facilities and analyzing actions during armed conflict to assess whether damage to UN facilities violated that law. In particular, Part Two first explores the meaning of “inviolability” in the Convention on the Privileges and Immunities of the United Nations to understand if and how it applies in the context of military operations, and demonstrates that inviolability does not encompass harm from military operations during armed conflict. This Part also applies the principle of lex specialis to demonstrate that even if one extends the principle of inviolability beyond its accepted understanding, LOAC is the appropriate legal framework for analyzing harm to UN facilities during armed conflict if there is a conflict between general international law on immunities of the UN and LOAC. Part Three of this article then examines how LOAC’s rules on military objectives, specially-protected objects, proportionality and precautions apply in practice when UN facilities located in areas of combat operations face direct or collateral consequences from those operations.