Designating official state entities as terrorist organizations raises challenges concerning the limits of state jurisdiction and compliance with international obligations. Focusing on the United States’ designation of the Islamic Revolutionary Guard Corps as a Foreign Terrorist Organization in 2019, this article examines the compatibility of that decision and its effects with sovereign equality, non-intervention, and state immunity. The central research question is how the designation of an official state entity as a terrorist organization, together with the implementation of resulting restrictions, should be assessed under international law. The study adopts a descriptive-analytical method based on library and documentary research. Its principal contribution is an analytical framework distinguishing the decision’s validity under domestic law from its international legality, and the designation itself from its implementing measures. Within this framework, reliance on United States domestic law does not, by itself, establish the international legality of the decision’s effects; likewise, the designated entity’s official status alone is insufficient to establish a breach of all the rules under consideration. The study concludes that the decision’s criminal, financial, and extraterritorial effects require separate assessment, identification of the relevant international obligation, and examination of the conditions constituting its breach. This framework enables a substantiated legal critique of the United States’ action while avoiding unsupported generalizations.