Groups considered by many to be terrorist and the countries where they are/were active:
- Abu Nidal Organization - international (went by the name of Black September during the 1972 Olympics in Munich)
- Abu Sayyaf - Philippines
- African National Congress - South Africa
- al-Qaeda - international
- Aum Supreme Truth - Japan
- The Angry Brigade - United Kingdom
- ETA (Basque Fatherland and Liberty) - Spain
- Contras - Nicaragua
- Death Squads - El Salvador
- Earth Liberation Front - United States
- Front de la Liberation du Quebec - Canada
- Hamas - Palestine/Israel
- Hizballah - Lebanon
- Continuity Irish Republican Army - Ireland, United Kingdom
- Provisional Irish Republican Army - Ireland, United Kingdom
- Irgun Gang - British mandate of Palestine
- Islamic Jihad - Egypt
- Japanese Red Army - Japan
- Jewish Defense League - United States (1969-1987; may have recently (2001) re-commenced terrorist activity)
- Ku Klux Klan - United States
- Khmer Rouge - Cambodia
- Kurdistan Workers Party (PKK) - Turkey
- Liberation Tigers of Tamil Eelam - Sri Lanka
- Loyalist Volunteer Force - Ireland, United Kingdom
- Montoneros - Argentina
- National Liberation Army - ELN in Columbia
- Orange Volunteers - Ireland, United Kingdom
- Palestine Liberation Organization - Palestine, Israel
- People Against Gangsterism and Drugs - South Africa
- Red Army Faction - Germany
- Red Brigades - Italy
- Revolutionary Armed Forces of Colombia (FARC) - Columbia
- Revolutionary United Front - Sierra Leone
- Shining Path - Peru
- Stern Gang - British mandate of Palestine
- Symbionese Liberation Army - United States
- Weathermen - United States