Ramzi bin al-Shibh

Ramzi Mohammed Abdullah bin al-Shibh (Arabic: رمزي محمد عبد الله بن الشيبة, romanized: Ramzī Muḥammad ʻAbd Allāh bin al-Shībh; born May 1, 1972) is a Yemeni terrorist who served as al-Qaeda's communications officer. He has been detained by the United States in the Guantanamo Bay detention camp (NSGB) since 2006. He was a "key facilitator" of the September 11 attacks in 2001.

In the mid-1990s, bin al-Shibh moved to Hamburg, Germany, for studies. There, he became close friends with September 11 hijackers Mohamed Atta, Ziad Jarrah, and Marwan al-Shehhi. They were members of the Hamburg cell, which planned the details of the attacks. bin al-Shibh was the only one of the four who failed to obtain a U.S. visa; he acted as an intermediary for the hijackers in the United States, by wiring money and passing on information from key al-Qaeda figures. After the attacks, bin al-Shibh was the first to be publicly identified by the U.S. as the "20th hijacker", for whom there have been several more possible candidates.

Bin al-Shibh has been in United States custody since he was captured in Karachi, Pakistan, in 2002. He was in custody of the Central Intelligence Agency (CIA) before being transferred to Guantanamo Bay in 2006. Finally charged in 2008 before a military commission, he and several others suspected in the 9/11 attacks went to trial beginning in May 2012. In 2023, a U.S. military judge ruled him too psychologically damaged to defend himself after CIA torture.