This article looks at the origins, purposes and conflicts of national interests and policies that were the primary influences in shaping the substance of the Arms Trade Treaty, which came into force at the end of 2014. It then proceeds to a more legally focussed analysis and, having identified several important issues which have had to remain undiscussed, concentrates on detailed examination and evaluation of the most important provisions of substance. These are firstly the scope of the Treaty—defining the equipment or materiel covered (Article 2). There follows analysis of the provisions which contain the obligations on exporting States, ranging from absolute prohibitions (Article 6) to ‘export assessments’ (Article 7), which in practice will be the most frequently applicable. The paper concludes by identifying several valuable provisions in the Treaty whilst also highlighting several significant weaknesses and omissions. It contends that evaluation of the Treaty's likely contribution to controlling the recognized evils of the arms trade is premature at this stage and, further, that efforts towards that end must focus on the practice and law of domestic administrative implementation, rather than international law.