Did NATO help the US after 911?

Yes, NATO invoked Article 5 of its treaty for the first time in response to the September 11, 2001 attacks, which states that an armed attack against one member is considered an attack against all. This led to NATO allies providing support to the U.S., including military assistance and operational participation in the subsequent War on Terror. Countries such as the UK, Canada, and others contributed troops and resources for operations in Afghanistan. This collective response underscored the alliance's commitment to mutual defense and solidarity.