Emmett Louis Till (July 25, 1941 – August 28, 1955) was an African American youth, who was 14 years old when he was abducted and lynched in Mississippi in 1955 after being accused of offending a white woman, Carolyn Bryant, in her family's grocery store. The brutality of his murder and the acquittal of his killers drew attention to the long history of violent persecution of African Americans in the United States. Till posthumously became an icon of the civil rights movement.

Till was born and raised in Chicago, Illinois. During summer vacation in August 1955, he was visiting relatives near Money, Mississippi, in the Mississippi Delta region. Till spoke to 21-year-old Carolyn Bryant, the white, married proprietor of a local grocery store. Although what happened at the store is a matter of dispute, Till was accused of flirting with, touching, or whistling at Bryant. Till's interaction with Bryant, perhaps unwittingly, violated the unwritten code of behavior for a black male interacting with a white female in the Jim Crow–era South. Several nights after the encounter, Bryant's husband Roy and his half-brother J. W. Milam, who were armed, went to Till's great-uncle's house and abducted Till, age 14. They beat and mutilated him before shooting him in the head and sinking his body in the Tallahatchie River. Three days later, Till's mutilated and bloated body was discovered and retrieved from the river.

Till's body was returned to Chicago, where his mother insisted on a public funeral service with an open casket, which was held at Roberts Temple Church of God in Christ. It was later said that "The open-coffin funeral held by Mamie Till Bradley exposed the world to more than her son Emmett Till's bloated, mutilated body. Her decision focused attention on not only American racism and the barbarism of lynching but also the limitations and vulnerabilities of American democracy." Tens of thousands attended his funeral or viewed his open casket, and images of Till's mutilated body were published in black-oriented magazines and newspapers, rallying popular black support and white sympathy across the United States. Intense scrutiny was brought to bear on the lack of black civil rights in Mississippi, with newspapers around the U.S. critical of the state. Although local newspapers and law enforcement officials initially decried the violence against Till and called for justice, they responded to national criticism by defending Mississippians, giving support to the killers.

In September 1955, an all-white jury found Bryant and Milam not guilty of Till's murder. Protected against double jeopardy, the two men publicly admitted in a 1956 interview with Look magazine that they had tortured and murdered Till, selling the story of how they did it for $4,000 (equivalent to $46,000 in 2024). Till's murder was seen as a catalyst for the next phase of the civil rights movement. In December 1955, the Montgomery bus boycott began in Alabama and lasted more than a year, resulting eventually in a U.S. Supreme Court ruling that segregated buses were unconstitutional. According to historians, events surrounding Till's life and death continue to resonate.

An Emmett Till Memorial Commission was established in the early 21st century. The county courthouse in Sumner was restored and includes the Emmett Till Interpretive Center. Fifty-one sites in the Mississippi Delta are memorialized as associated with Till. The Emmett Till Antilynching Act, an American law which makes lynching a federal hate crime, was signed into law on March 29, 2022, by President Joe Biden.

Emmett Till was born to Mamie and Louis Till on July 25, 1941, in Chicago. Emmett's mother, Mamie [née Carthan], was born in the small Delta town of Webb, Mississippi. The Delta region encompasses the large, multi-county area of northwestern Mississippi in the watershed of the Yazoo and Mississippi rivers. When Carthan was two years old, her family moved to Argo, Illinois, near Chicago, as part of the Great Migration of rural black families out of the South to the North to escape violence, lack of opportunity and unequal treatment under the law. Argo received so many Southern migrants that it was named "Little Mississippi"; Carthan's mother's home was often used by other recent migrants as a way station while they were trying to find jobs and housing.

Mississippi was the poorest state in the U.S. in the 1950s, and the Delta counties were some of the poorest in Mississippi. Mamie Carthan was born in Tallahatchie County, where the average income per white household in 1949 was $690 (equivalent to $9,100 in 2024). For black families, the figure was $462 (equivalent to $6,100 in 2024). In the rural areas, economic opportunities for blacks were almost nonexistent. They were mostly sharecroppers who lived on land owned by whites. Blacks had essentially been disenfranchised and excluded from voting and the political system since 1890 when the white-dominated legislature passed a new constitution that raised barriers to voter registration. Whites had also passed ordinances establishing racial segregation and Jim Crow laws.

Mamie largely raised Emmett with her mother; she and Louis Till separated in 1942 after Mamie discovered that he had been unfaithful. Louis later assaulted Mamie, choking her to unconsciousness, to which she responded by throwing scalding water at him. For violating court orders to stay away from Mamie, Louis Till was forced by a judge in 1943 to choose between jail or enlisting in the U.S. Army. In 1945, a few weeks before his son's fourth birthday, Louis Till was court-martialed and executed in Italy for the murder of an Italian woman and the rape of two others.