John Allen Muhammad (December 31, 1960 – November 10, 2009) was an American convicted murderer from Baton Rouge, Louisiana. He, along with his partner/accomplice Lee Boyd Malvo (aged 17), a native of Jamaica, West Indies, carried out the Beltway sniper attacks of October 2002, killing 17 people. Muhammad and Malvo were arrested in connection with the attacks on October 24, 2002, following tips from alert citizens. Although the pair's actions were classified by the media as psychopathy attributable to serial killer characteristics, whether or not their psychopathy meets this classification or that of a spree killer is debated by researchers.

Born as John Allen Williams, Muhammad joined the Nation of Islam in 1987 and later changed his surname to Muhammad.

At Muhammad's trial, the prosecutor claimed that the rampage was part of a plot to kill his ex-wife and regain custody of his children, but the judge ruled that there was insufficient evidence to support this argument.

His trial for one of the murders (that of Dean Harold Meyers in Prince William County, Virginia) began in October 2003, and the following month he was found guilty of capital murder. Four months later he was sentenced to death. While awaiting execution in Virginia, in August 2005, he was extradited to Maryland to face some of the charges there. He was convicted of six counts of first-degree murder on May 30, 2006. Upon completion of the trial activity in Maryland, Muhammad was returned to Virginia's death row pending an agreement with another state or the District of Columbia seeking to try him. He was not tried on additional charges in other Virginia jurisdictions, and faced potential trials in three other states and the District of Columbia involving other murders and attempted murders. All appeals of his conviction for killing Dean Harold Meyers had been made and rejected. Appeals for Muhammad's other trials remained pending at the time of his execution.

Muhammad was executed by lethal injection on November 10, 2009, at 9:06 p.m. EST at the Greensville Correctional Center near Jarratt, Virginia, and was pronounced dead at 9:11 p.m. EST. Muhammad declined to make a final statement.

Police followed a lead in which Muhammad or Malvo left a note at one of the shootings to tell the police to investigate a liquor store robbery-murder that had occurred in Montgomery, Alabama. Investigators responding to that crime scene found one of the suspects had dropped a magazine with his fingerprints on it; these were subsequently identified as belonging to a 17-year-old Jamaican illegal immigrant, Lee Boyd Malvo, whose prints were on file with the INS. Malvo was known to associate with Muhammad. They had lived together in Tacoma, Washington, for around one year, where Malvo used the alias, John Lee Malvo.

Muhammad's identification led to the discovery that he had purchased a former police car, a blue Chevrolet Caprice, in New Jersey on September 11, 2002.