The terrorist group responsible for the September 11, 2001 attacks was al- Qaeda, a militant Islamist organization founded by Osama bin Laden. On that day, 19 terrorists affiliated with al-Qaeda hijacked four commercial airliners, crashing two into the Twin Towers of the World Trade Center in New York City, one into the Pentagon in Virginia, and the fourth in a field in Pennsylvania after passengers intervened. These coordinated suicide attacks killed nearly 3,000 people

. The FBI and CIA quickly linked the hijackers to al-Qaeda, and Osama bin Laden later admitted his role in orchestrating the attacks, confirming al- Qaeda's responsibility. Key figures in planning the attacks included bin Laden, Khalid Sheikh Mohammed, and Ramzi bin al-Shibh

. The attacks were motivated by al-Qaeda's opposition to U.S. foreign policy, particularly its support for Israel and governments in the Middle East

. In summary, al-Qaeda, led by Osama bin Laden, was the terrorist group responsible for the 9/11 attacks