The 16th Street Baptist Church bombing was a white supremacist terrorist bombing of the 16th Street Baptist Church in Birmingham, Alabama, on Sunday, September 15, 1963. Four members of a local Ku Klux Klan chapter planted 19 sticks of dynamite attached to a timing device beneath the steps located on the east side of the church. Described by Martin Luther King Jr. as "one of the most vicious and tragic crimes ever perpetrated against humanity," the explosion at the church killed four girls and injured between 14 and 22 other people.

Although the FBI had concluded in 1965 that the 16th Street Baptist Church bombing had been committed by four known Klansmen and segregationists: Thomas Edwin Blanton Jr., Herman Frank Cash, Robert Edward Chambliss, and Bobby Frank Cherry, no prosecutions were conducted until 1977, when Robert Chambliss was tried by Alabama Attorney General Bill Baxley and convicted of the first-degree murder of one of the victims, 11-year-old Carol Denise McNair.

As part of a revival effort by states and the federal government to prosecute cold cases from the civil rights era, the state conducted trials in the early 21st century of Thomas Edwin Blanton Jr. and Bobby Cherry, who were each convicted of four counts of murder and sentenced to life imprisonment in 2001 and 2002, respectively. Future United States Senator Doug Jones successfully prosecuted Blanton and Cherry. Herman Cash had died in 1994, and was never charged with his alleged involvement in the bombing.

The 16th Street Baptist Church bombing marked a turning point in the United States during the civil rights movement and also contributed to support for the passage of the Civil Rights Act of 1964 by Congress.