The principle of proportionality between crime and punishment constitutes one of the fundamental pillars of criminal justice and occupies a central position within the system of international criminal law, particularly in the practice of the International Criminal Court. This principle requires that the penal response to criminal conduct correspond to the gravity, nature, and consequences of the committed offense, while simultaneously respecting human dignity and the fundamental rights of the accused. The present study focuses on crimes such as genocide, crimes against humanity, and war crimes, and examines how the principle of proportionality is realized in the process of determining and enforcing punishments in the jurisprudence of the International Criminal Court. In this context, the study analyzes the criteria influencing the assessment of proportionality, including the degree of participation of the offender, aggravating and mitigating circumstances, the purposes of punishment, and humanitarian considerations.The research also addresses the legal, political, and structural challenges affecting the full implementation of the principle of proportionality, such as the abolition of the death penalty within the ICC system, the dependence of enforcement on state cooperation, the diversity of domestic legal systems, and the impact of political considerations on the functioning of international criminal justice. The findings indicate that although the International Criminal Court emphasizes the principle of proportionality at the normative level, its practical implementation faces certain limitations that may affect the effectiveness and legitimacy of its judgments. The research methodology adopted in this article is descriptive–analytical. Accordingly, the relevant concepts, theoretical foundations, and legal frameworks concerning the principle of proportionality are first described on the basis of international legal instruments and the Statute of the International Criminal Court. Subsequently, through content analysis of judicial practice, issued judgments, and doctrinal views in international criminal law, the manner of implementation and the practical challenges of this principle are critically examined. Data have been collected through library-based research, including the study of legal documents, treaties, judicial decisions, and authoritative academic sources.