Juanita Abernathy, who helped organize the Montgomery bus boycott and took part in other pivotal protests at the outset of the civil rights era alongside the Rev. Dr. Ralph Abernathy, her husband and a leader of the movement, died on Thursday at a hospital in Atlanta. She was 87.

The cause was a stroke, her son Kwame Abernathy said.

Ms. Abernathy organized, marched and campaigned for voting rights for African-Americans and to integrate the schools in the 1950s and ’60s. She taught voter-education classes, housed Freedom Riders and accompanied her husband to the 1963 March on Washington for Jobs and Freedom and to the Selma-to-Montgomery, Ala., marches in 1965.

Representative John R. Lewis, the Georgia Democrat and former civil rights-era leader, said in a statement that Ms. Abernathy had been “my sister on the front lines” in the struggle for change.