What Is Terrorism?

 Terrorists have sought to achieve their political agendas all over the world.

Video video 4:25

What the World’s Terrorist Groups Have in Common

Strong ideology motivates those who commit terrorism, no matter their goals.

Interactive interactive

Who Counts As a Terrorist?

From foreign groups to domestic threats, how does the U.S. government define terrorism?

Infographic infographic

Terrorism by the Numbers

What the numbers behind terrorism—and the process of getting to them—reveal.

Chart chart

Radicalization and Right-Wing Extremism

Learn how the domestic terror threat has evolved since 9/11.

Photo photo

Terrorism and the Media

Terrorism is often described as requiring the “oxygen of publicity.”

Video video 3:30

U.S. Counterterrorism Since 1945

The history of counterterrorism in the United States is more than a list of policies. It shows how the definition of terrorism and the agencies and tools used to pursue those who commit it have evolved over time.

Timeline timeline

Tools of Counterterrorism

National security experts have a range of options available as they work to prevent terrorism.

Video video 2:45

How a Single Phrase Defined the War on Terror

The open-ended scope of the 2001 Authorization for Use of Military Force has justified counterterrorism policy for two decades—and counting.

Infographic infographic

The Terrorist Money Trail

What the challenges of targeting terrorists’ finances tell us about the evolving terrorist threat.

Infographic infographic

Terrorism Module Assessment

Questions to check your understanding.

Interactive interactive

Terrorism Reading List

Supplemental readings and other resources.

Summary summary

How Terrorism Affects You

The following articles explore the effects of terrorism on individuals, communities, and societies.

More From CFR

    From Tragedy to Prevention: Lessons Learned From Terrorist Attacks

    Experts discuss recent terrorist attacks across Europe and how they might shape future counterterrorism efforts.

    Photo: Darren Staples/Reuters

    Women Are Critical to Counterterrorism

    Experts argue that efforts to detect radicalization, challenge extremist narratives, and stop terrorist threats are more successful with women involved.

    Photo: Christopher Herwig/Reuters

    The Taliban

    A multimedia overview spanning the group’s rise in the 1990s to its enduring insurgency against U.S. and allied forces.

    Photo: Reuters