Clive Adrian Stafford Smith OBE (born 9 July 1959) is a British attorney who specialises in the areas of civil rights and working against capital punishment in the United States. He worked to overturn death sentences for convicts, and helped found the not-for-profit Louisiana Capital Assistance Center in New Orleans. By 2002 this was the "largest capital defence organisation in the South." He was a founding board member of the Gulf Region Advocacy Center, based in Houston, Texas.

In addition, he has represented more than 80 of the detainees held as enemy combatants since 2002 at the Guantanamo Bay detention camp. As of February 2021, a total of 40 men are still held there.

In August 2004, Stafford Smith returned from the U.S. to live and work in the United Kingdom. He is the co-founder of Reprieve, a human rights not-for-profit organisation. He left after 15 years, and has now established a new non-profit called 3DCentre. In 2005, he received the Gandhi International Peace Award.

Born in Cambridge and educated at Old Buckenham Hall School and Radley College, Clive Stafford Smith studied journalism as a Morehead Scholar at the University of North Carolina at Chapel Hill. He followed this degree with another in law at Columbia University in New York. He is licensed to practise law in the state of Louisiana.

Stafford Smith worked for the Southern Prisoners' Defense Committee, based in Atlanta, now known as the Southern Center for Human Rights, and on other campaigns to help convicted defendants sentenced to capital punishment. He was featured in Fourteen Days in May (1987), a documentary showing the fortnight prior to the execution of Edward Earl Johnson in Mississippi State Penitentiary. It was aired on the BBC. Stafford Smith had acted as Johnson's attorney and was seen trying to halt the execution. In a follow-up documentary, Stafford Smith conducted his own investigation into the murder case for which Johnson had been executed.

In 1993, he helped set up a new justice center for prisoner advocacy in New Orleans. Formerly named the Louisiana Crisis Assistance Center, it is now known as the Louisiana Capital Assistance Center (LCAC). He represented the paedophile Ricky Langley, who was convicted of murder and sentenced to death. The jurors accepted that the accused was suffering from mental illness, but condemned Langley to capital punishment. The conviction was reversed, and Stafford Smith facilitated a meeting where Ricky apologised to the mother of his victim, Jeremy Guillory. Lorilei Guillory asked the DA to drop the death penalty, which he denied. She testified that Ricky should be in a mental hospital rather than prison, saying "I think he is mentally ill."

In 2002, Stafford Smith became a founding board member of the Gulf Region Advocacy Center, a non-profit law office based in Houston, Texas. It was designed to bring his legal methods developed at LCAC into the "capital of capital punishment", as Texas had the highest number of executions in the United States.

After returning to Britain, Stafford Smith worked as the founder of Reprieve, a British non-profit NGO that is opposed to the death penalty. During his career in the U.S., by 2002 Stafford Smith had lost appeals in six death penalty cases, but had won nearly 300, earning reprieves from execution for those convicts and exonerating a number of them.