The War on Terror Campaign which is also noted as the Global War on Terror or the War on Terrorism is an permanent international war campaign launched in 2001 by the United States of America and the United Kingdom with the support of other NATO and non-NATO countries.

The campaign was launched with the U.S./U.K. invasion of Afghanistan in response to the September 11 terrorist attacks. Since then, other operations have commenced, the largest being the War in Iraq, beginning with a 2003 invasion. Originally, it was waged against al-Qaeda and other terrorist organizations with the purpose of eliminating them.

The phrase War on Terror was first used by former US President George W. Bush and other high-ranking US officials to denote a global military, political, legal and ideological struggle against organizations designated as terrorist and regimes that were accused of having a connection to them or providing them with support or were perceived, or presented as posing a threat to the US and its allies in general. It was typically used with a particular focus on militant Islamists and al-Qaeda.

Although the term is not officially used by the administration of President Barack Obama (which instead uses the term Overseas Contingency Operation), it is still commonly used by politicians, in the media and officially by some aspects of government, such as the Army’s Global War on Terrorism Service Medal.