Global Terrorism: Definition, Statistics, Ideology, and the Religion Question

This page documents the global record of terrorism: what terrorism is defined as, who commits it, and what the data shows about the relationship between ideology, religion, and mass violence. The data does not support the claim that "terrorism has no religion" — but it also requires precision about which data set, which definition, and which geography one is examining.

There is no single universally agreed definition of terrorism. The major operational definitions share common elements:

UN Security Council Resolution 1566 (2004):

"Criminal acts, including against civilians, committed with the intent to cause death or serious bodily injury, or taking of hostages, with the purpose to provoke a state of terror in the general public or in a group of persons or particular persons, intimidate a population or compel a government or an international organization to do or to abstain from doing any act."

FBI (United States):

"Violent, criminal acts committed by individuals and/or groups to further ideological goals stemming from domestic influences, such as those of a political, religious, social, racial, or environmental nature."

Global Terrorism Database (GTD) — University of Maryland, START Center: An incident is classified as terrorism if it meets all three criteria:

1. The act is intentional
2. The act entails some level of violence or threat of violence
3. The perpetrators of the act are sub-national actors (not a state)

And at least two of the following:

• The act has a political, economic, religious, or social goal
• There is evidence of an intention to coerce, intimidate, or convey a message to a larger audience beyond the immediate victims
• The act is outside the precepts of International Humanitarian Law

Key definitional disputes:

• State terrorism: Most definitions exclude state actors, which means aerial bombing campaigns, cluster munitions on civilians, and systematic torture by governments are not counted — regardless of intent or effect. Critics argue this asymmetry undercounts state violence while focusing exclusively on non-state violence.
• Resistance vs. terrorism: Whether Palestinian bombings, IRA attacks, or ANC sabotage constitute terrorism or legitimate resistance is contested. The GTD counts them as terrorism if they meet the criteria; others disagree.
• Hate crimes vs. terrorism: In the United States, shootings motivated by racial or religious hatred may be charged as hate crimes rather than terrorism, which affects how they appear in domestic terrorism statistics.

For this analysis, we use the GTD definition and cross-reference with the Institute for Economics and Peace (IEP) Global Terrorism Index.

Source: IEP Global Terrorism Index 2023; GTD (START, University of Maryland)

The peak in 2014 was driven primarily by the Islamic State (IS) seizing large territories in Iraq and Syria and by Boko Haram's peak activity in northeastern Nigeria. The subsequent decline reflects military campaigns against IS and Boko Haram, not a reduction in the underlying ideology.

Geographic concentration: In 2022, five countries accounted for approximately 80% of global terrorism deaths: Burkina Faso, Mali, Somalia, Nigeria, and Iraq. All five countries are experiencing active Islamist insurgencies as the primary driver of terrorism deaths.

Estimated share of global terrorism deaths 2000–2022 by primary ideology of perpetrators:

Notes on this data:

• "Islamist" here means groups that explicitly justify their violence through Islamic scripture and/or declare the goal of establishing Islamic governance (caliphate, sharia state). This is not a statement about all Muslims or Islam as a religion — it is a description of what these groups state as their motive.
• The dominance of Islamist groups in the death count is especially pronounced because of the scale of individual attacks: the 9/11 attacks (2,977 deaths), the IS campaign in Iraq/Syria (tens of thousands), and Boko Haram's prolonged insurgency in Nigeria (estimated 350,000+ deaths from 2009–2022 including conflict deaths) dwarf any single far-right incident.
• In Western democracies specifically, the far-right domestic terrorism share is significantly higher — roughly 25–35% of deaths from terrorism in Western Europe and North America (2001–2022), with Islamist attacks accounting for the majority of deaths in that region.
• The FBI's 2022 Domestic Terrorism report identified Racially/Ethnically Motivated Violent Extremism (REMVE — primarily white supremacist) and Anti-Government Extremism as the two largest categories of domestic terrorism cases in the United States by case count. International (Islamist) terrorism produced more mass-casualty events in the same period.

Source: IEP Global Terrorism Index 2023; GTD (START, University of Maryland 2021); RAND Corporation, "Trends in Global Terrorism" (2017); FBI Terrorism Statistics (2022).

Death estimates are approximate, compiled from GTD, ACLED, IEP, and conflict tracking databases. They include combatant and civilian deaths from terrorist acts attributed to these groups.

This table covers attacks with 10+ deaths or historically significant attacks in Western countries. It is illustrative, not exhaustive. Complete data: Global Terrorism Database (200,000+ incidents, 1970–2020).

Note: Jan 6, 2021 is included as an event that multiple prosecutors and legal bodies have described as involving elements of terrorism; whether it constitutes terrorism per the formal definition is legally contested.

For international attacks in Western countries (US, UK, EU, Australia) from 2001–2022:

For US domestic terrorism (2000–2022):

• Born in the United States: The majority of both far-right domestic terrorism perpetrators and Islamist-inspired terrorism perpetrators in the US were US citizens or legal residents at the time of their attack (Fort Hood, Orlando, San Bernardino*, Boston*, Oklahoma City).
• *Farook was US-born; Malik was a Pakistani national with a K-1 visa. Tsarnaev was a naturalized citizen.
• Far-right domestic: McVeigh, Roof, Bowers, Crusius — all US-born citizens.

Key finding: The "foreign-born terrorism" framing captures some attacks (9/11 pilots, Nice, Berlin) but misses the significant portion of Islamist-inspired attacks carried out by citizens of Western countries who radicalized domestically or via online networks.

The claim: "Terrorism has no religion" — often cited in the aftermath of Islamist attacks, implying that the perpetrators' religious ideology is irrelevant or incidental to their violence.

What the data shows:

1. The groups themselves explicitly state their religious motivation. The Islamic State published a theological journal (Dabiq, later Rumiyah) explaining its scriptural justification for every act. Al-Qaeda's declarations were built around fatwas. Boko Haram's name translates roughly to "Western education is sin/forbidden" in Hausa. These are not analysts attributing religion retroactively — these are the groups' own stated reasons.

2. The death toll is not equally distributed across ideologies. Between 2001 and 2022, Islamist groups were responsible for an estimated 65–75% of global terrorism deaths. No other ideological category comes close at the global level.

3. "Religion" vs. "Islam": The claim is sometimes made more precisely: not that religion is irrelevant but that the perpetrators are "perverting" Islam. This is a theological argument, not an empirical one. Whether they are correctly interpreting Islam is a matter of religious scholarship — but what they believe they are doing is a matter of documented fact.

4. The false equivalence with far-right domestic terrorism: In Western domestic contexts, far-right terrorism is a genuine and growing threat. This does not make it equivalent in scale to global Islamist terrorism. In terms of deaths globally: Islamist attacks produced roughly 10–20× more deaths than far-right attacks in the same period.

5. Not all perpetrators are devout Muslims. Several Islamist attackers (Omar Mateen, Mohamed Lahouaiej-Bouhlel) were documented to have been personally non-devout, had histories of substance use or sexual behavior inconsistent with strict Islam, and radicalized rapidly before their attacks. This complicates but does not eliminate the ideological factor — they self-identified with the ideology at the moment of the attack.

Counter-arguments that have merit:

• Most Muslims do not engage in terrorism, and most victims of Islamist terrorism are Muslims in Muslim-majority countries.
• Structural and geopolitical factors (colonial history, Western military interventions, failed states) contribute to radicalization — ideology is not the only variable.
• Labeling terrorism by religion when applied selectively ("Islamic terrorism" but not "Christian terrorism" for the IRA or LRA) introduces inconsistency.

These counter-arguments do not invalidate the primary data finding: that Islamist ideology, as a stated and documented motivation, accounts for the majority of global terrorism deaths.

• Global Terrorism Database (GTD) — National Consortium for the Study of Terrorism and Responses to Terrorism (START), University of Maryland. The most comprehensive academic terrorism database: 200,000+ incidents from 1970–2020, with detailed coding for perpetrator, ideology, method, casualties.
• IEP Global Terrorism Index 2023 — Annual report from the Institute for Economics and Peace; tracks deaths, incidents, and trends by country and group.
• ACLED (Armed Conflict Location and Event Data Project) — Real-time conflict tracking; especially strong for sub-Saharan Africa and Asia.
• FBI Terrorism Statistics — US domestic and international terrorism statistics.
• RAND Terrorism Database — Academic analysis with longer-term trend data.
• UN Office of Counter-Terrorism (UNOCT) — UN-level monitoring and definition framework.
• Europol TE-SAT (EU Terrorism Situation and Trend Report) — Annual EU-wide terrorism statistics including domestic and Islamist trends.
• MEMRI (Middle East Media Research Institute) — Translation and documentation of primary source materials from Islamist groups.
• SITE Intelligence Group — Real-time monitoring of terror group communications and claims.