The unprecedented terrorist attacks at the key economic, political, and military power centres in the United States on 11 September 2001 led to immediate restrictive measures among States in the Global North, and the international community as a whole. The perceived unprecedented threat of international terrorism had to be confronted with nothing less than a global war on terrorism. The prioritisation of security and the proactive measures taken to address internal and external terrorist threats had an especially pernicious effect on those who sought asylum from persecution as States introduced new statutory, regulatory, and procedural measures to combat terrorism. This article reviews and analyses the leading superior court decisions dealing with the exclusion of terrorists under Article 1F of the 1951 Geneva Convention Relating to the Status of Refugees and its 1967 Protocol in five common law jurisdictions: Canada, the United States, the United Kingdom, Australia, and New Zealand. It focuses on the key legal concepts of complicity and culpability that are the basis for determining whether a refugee applicant ought to be excluded from Convention refugee status when it is alleged that they are involved in terrorist activities. The article argues that the superior courts in these five common law jurisdictions have followed each others judgments in this area closely and have influenced each others precedential decisions. The superior courts in these States have also been influenced by the judgments of international courts and especially the Rome Statute of the International Criminal Court. Indeed, the most recent decisions of the Supreme Courts of the United Kingdom and New Zealand draw on the Rome Statute and the concept of joint criminal enterprise liability as a basis for determining whether an asylum applicant should be excluded for their alleged involvement in terrorist activities. The article concludes with a call for an internationally accepted definition of what constitutes terrorism. It is argued that if the international community and States could come to an agreement on a common definition of terrorism this would facilitate the purposive and principled application and interpretation of the exclusion clauses under the 1951 Geneva Convention and its 1967 Protocol and the developing jurisprudence in the area of exclusion on the basis of a refugee applicants alleged involvement and participation in terrorist activities.