As a label, “terrorism” or “terrorist” has a strong stigmatizing effect, and has long been used strategically to delegitimize enemies. In addition, “terrorism” is a legal concept that is addressed in a wide range of international law regimes. Acts of terrorism and the challenges they pose have led the international community to adopt numerous instruments to address them. In the framework of the adoption of the Rome Statute in 1998 and the establishment of the International Criminal Court, a mechanism was established to deal with international crimes. In 1994, the International Law Commission, on the Statute of the International Criminal Court, proposed to include another category of crimes within the jurisdiction of the Court, including “treaty crimes” including terrorism, drug trafficking, apartheid and grave breaches of the four Geneva Conventions of 1949. The lack of consensus on this matter led to the exclusion of terrorism from the jurisdiction of the Court. The events of September 11, 2001, unlike other events, focused the attention of the international community on the phenomenon of terrorism. The well-known issues in the international legal system are among the challenges that terrorism has created.