The application of penalties in public international law represents a fundamental mechanism for maintaining international order and ensuring compliance with legal obligations among states and other international actors. Penalties, in this context, serve as tools to deter violations, provide accountability, and uphold the principles of justice within the international community. This research examines the concept, forms, and implementation of penalties in public international law, analyzes their legal basis under international treaties and customary law, and highlights their role in addressing breaches of international norms, with a focus on their effectiveness and challenges in contemporary practice.