Relying on the methodology explained in Chapter 3, Chapter 5 clarifies the duty bearer of the weapons review obligation — ‘a High Contracting Party’ — and considers the process and standard of review covered by the terms ‘study, development, acquisition or adoption’, ‘to determine’, ‘in some or all circumstances’ and ‘this Protocol or … any other rule of international law’. It concludes that the Article 36 obligation rests on each State Party to Additional Protocol I and allows for variations in terms of form and procedure. While the establishment of a standing or permanent mechanism is not required as a matter of law, States regularly developing or purchasing weapons must adopt a certain internal approach or coherent national measures to examine the legality of new weapons. The legal standard of review indisputably comprises treaty and customary law of armed conflict. However, the proposition advanced in the legal literature to extend the review scope to human rights is unlikely to enhance protection already offered under the law of armed conflict and thus justify the inclusion of such rights in the Article 36 analysis. [181 words]