This chapter begins with an examination of the concept of defences in international criminal law before retracing the development and the application of the defence of duress in national and international law. It also sets out the theoretical differences between duress as a justification defence and as an excuse defence. A theoretical and jurisprudential analysis of the defence illustrates that because duress has so far been viewed as a justification under international criminal law, it is unlikely to be successfully invoked by children or adults. However, it appears that the International Criminal Court (ICC) Statute may allow for a wider use of the defence of duress. This chapter also explains the relevance of the ICC Statute in determining the requirements of duress under international law despite the fact that the ICC has no jurisdiction to prosecute children.