Hamdan v. Rumsfeld, 548 U.S. 557 (2006), is a United States Supreme Court case in which the Court held that military commissions set up by the Bush administration to try detainees at Guantanamo Bay violated both the Uniform Code of Military Justice (UCMJ) and the Geneva Conventions ratified by the U.S.

The Guantanamo military commissions were established by President George W. Bush through a military order on November 13, 2001, to try certain non-citizen terrorism suspects at the Guantanamo Bay prison. To date, there have been a total of eight convictions in the military commissions, six through plea agreements. Several of the eight convictions have been overturned in whole or in part on appeal by U.S. federal courts.