The principle of legality is an integral part of international criminal law (icl). International criminal courts and tribunals (iccts) have applied a ‘soft’ version of legality that has seldom operated as a meaningful curb upon their decisions. This article argues that, as the field of icl continues to mature and develop, its legitimacy and effectiveness would be enhanced if iccts applied a stricter version of legality. It explores the constituent elements of the principle- the doctrines of non-retroactivity, specificity, foreseeability and strict construction- examining how they have been applied in the past and suggesting ways to apply them in the future. The article argues that iccts should strive to set the gold standard when it comes to adherence to the principle of legality. This has the benefit of better protecting the rights of the accused, thereby ensuring a more effective and legitimate system of law.