A List of Terrorist Groups by Type

From Pre-Modern to Present-Day

KKK rally in Illinois
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While there is no universally agreed-upon or legally binding definition of a terrorist act, the U.S. gives it a good try in Title 22 Chapter 38 U.S. Code § 2656f, by defining terrorism as an act of "premeditated, politically motivated violence perpetrated against noncombatant targets by subnational groups or clandestine agents." Or, in brief, the use of violence or threat of violence in the pursuit of political, religious, ideological, or social objectives.

What we do know is that terrorism is nothing new. Even a cursory glance over the centuries reveals a startling list of groups for whom some form of violence is justified to achieve social, political, and religious change.

Terrorism in Early History

Most of us think of terrorism as a modern phenomenon. After all, many of the terrorist groups listed below rely or have relied on the mass media to spread their message through non-stop coverage. However, there are some pre-modern groups who used terror to achieve their ends, and who are often considered precursors to modern terrorists. For instance, the Sicarii, organized in the first century in Judea to protest Roman rule or the Thugee cult of assassins in ancient India who wreaked havoc and destruction in the name of Kali.


Many groups committed to socialist revolution or the establishment of socialist or communist states arose in the last half of the 20th century, and many are now defunct. The most prominent included:

National Liberation

National liberation is historically among the most potent reasons that extremist groups turn to violence to achieve their aims. There are many of these groups, but they have included:


There has been a rise in religiosity globally since the 1970s and, with it, a rise in what many analysts call religious terrorism. It would be more accurate to call groups such as Al Qaeda religious-political, or religious-nationalist. We call them religious because they use a religious idiom and shape their "mandate" in divine terms. Their goals, however, are political: recognition, power, territory, concessions from states, and the like. Historically, such groups have included:

  • Al Qaeda (transnational, Islamist)
  • Aum Shinrikyo (renamed Aleph; Japanese, with various influences, including Hindu and Buddhist)
  • Ku Klux Klan (U.S., Christian)
  • Abu Sayyaf (Philippines, Islamist)
  • Egyptian Islamic Jihad
  • Hamas (Palestinian, Islamist) (Hamas is designated by the U.S. and other governments as a terrorist group, but it is also the elected government of the Palestinian Authority)
  • Hezbollah (Hezbollah is designated as a terrorist organization by the U.S. and other governments, but others argue it should be considered a movement, rather than a terrorist group)

State Terrorism

Most states and transnational organizations (like the United Nations) define terrorists as non-state actors. This is often a highly contentious issue, and there are long-standing debates in the international sphere over a few states in particular. For instance, Iran and other Islamic states have long accused Israel of supporting terrorist acts in the surrounding settlements, Gaza, and elsewhere. Israel, on the other hand, contends it is fighting for its right to exist free of terror. There are some states or state actions in history over which there's no dispute, though, such as in Nazi Germany or Stalinist Russia.